Merging upstream version 9.0.3.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

12 files changed, 403 insertions, 190 deletions

diff --git a/sqlglot/__init__.py b/sqlglot/__init__.py
index 7841c11..a780f96 100644
--- a/sqlglot/__init__.py
+++ b/sqlglot/__init__.py
@@ -24,7 +24,7 @@ from sqlglot.parser import Parser
 from sqlglot.schema import MappingSchema
 from sqlglot.tokens import Tokenizer, TokenType
 
-__version__ = "9.0.1"
+__version__ = "9.0.3"
 
 pretty = False
 
diff --git a/sqlglot/dataframe/sql/column.py b/sqlglot/dataframe/sql/column.py
index 2391080..e66aaa8 100644
--- a/sqlglot/dataframe/sql/column.py
+++ b/sqlglot/dataframe/sql/column.py
@@ -5,7 +5,7 @@ import typing as t
 import sqlglot
 from sqlglot import expressions as exp
 from sqlglot.dataframe.sql.types import DataType
-from sqlglot.helper import flatten
+from sqlglot.helper import flatten, is_iterable
 
 if t.TYPE_CHECKING:
     from sqlglot.dataframe.sql._typing import ColumnOrLiteral
@@ -134,10 +134,14 @@ class Column:
         cls, column: t.Optional[ColumnOrLiteral], callable_expression: t.Callable, **kwargs
     ) -> Column:
         ensured_column = None if column is None else cls.ensure_col(column)
+        ensure_expression_values = {
+            k: [Column.ensure_col(x).expression for x in v] if is_iterable(v) else Column.ensure_col(v).expression
+            for k, v in kwargs.items()
+        }
         new_expression = (
-            callable_expression(**kwargs)
+            callable_expression(**ensure_expression_values)
             if ensured_column is None
-            else callable_expression(this=ensured_column.column_expression, **kwargs)
+            else callable_expression(this=ensured_column.column_expression, **ensure_expression_values)
         )
         return Column(new_expression)
 
diff --git a/sqlglot/dataframe/sql/functions.py b/sqlglot/dataframe/sql/functions.py
index 4c6de30..bc002e5 100644
--- a/sqlglot/dataframe/sql/functions.py
+++ b/sqlglot/dataframe/sql/functions.py
@@ -1,7 +1,6 @@
 from __future__ import annotations
 
 import typing as t
-from inspect import signature
 
 from sqlglot import expressions as glotexp
 from sqlglot.dataframe.sql.column import Column
@@ -24,17 +23,15 @@ def lit(value: t.Optional[t.Any] = None) -> Column:
 
 
 def greatest(*cols: ColumnOrName) -> Column:
-    columns = [Column.ensure_col(col) for col in cols]
-    return Column.invoke_expression_over_column(
-        columns[0], glotexp.Greatest, expressions=[col.expression for col in columns[1:]] if len(columns) > 1 else None
-    )
+    if len(cols) > 1:
+        return Column.invoke_expression_over_column(cols[0], glotexp.Greatest, expressions=cols[1:])
+    return Column.invoke_expression_over_column(cols[0], glotexp.Greatest)
 
 
 def least(*cols: ColumnOrName) -> Column:
-    columns = [Column.ensure_col(col) for col in cols]
-    return Column.invoke_expression_over_column(
-        columns[0], glotexp.Least, expressions=[col.expression for col in columns[1:]] if len(columns) > 1 else None
-    )
+    if len(cols) > 1:
+        return Column.invoke_expression_over_column(cols[0], glotexp.Least, expressions=cols[1:])
+    return Column.invoke_expression_over_column(cols[0], glotexp.Least)
 
 
 def count_distinct(col: ColumnOrName, *cols: ColumnOrName) -> Column:
@@ -194,7 +191,7 @@ def log2(col: ColumnOrName) -> Column:
 def log(arg1: t.Union[ColumnOrName, float], arg2: t.Optional[ColumnOrName] = None) -> Column:
     if arg2 is None:
         return Column.invoke_expression_over_column(arg1, glotexp.Ln)
-    return Column.invoke_expression_over_column(arg1, glotexp.Log, expression=Column.ensure_col(arg2).expression)
+    return Column.invoke_expression_over_column(arg1, glotexp.Log, expression=arg2)
 
 
 def rint(col: ColumnOrName) -> Column:
@@ -310,7 +307,7 @@ def hypot(col1: t.Union[ColumnOrName, float], col2: t.Union[ColumnOrName, float]
 
 
 def pow(col1: t.Union[ColumnOrName, float], col2: t.Union[ColumnOrName, float]) -> Column:
-    return Column.invoke_anonymous_function(col1, "POW", col2)
+    return Column.invoke_expression_over_column(col1, glotexp.Pow, power=col2)
 
 
 def row_number() -> Column:
@@ -340,14 +337,13 @@ def approxCountDistinct(col: ColumnOrName, rsd: t.Optional[float] = None) -> Col
 def approx_count_distinct(col: ColumnOrName, rsd: t.Optional[float] = None) -> Column:
     if rsd is None:
         return Column.invoke_expression_over_column(col, glotexp.ApproxDistinct)
-    return Column.invoke_expression_over_column(col, glotexp.ApproxDistinct, accuracy=Column.ensure_col(rsd).expression)
+    return Column.invoke_expression_over_column(col, glotexp.ApproxDistinct, accuracy=rsd)
 
 
 def coalesce(*cols: ColumnOrName) -> Column:
-    columns = [Column.ensure_col(col) for col in cols]
-    return Column.invoke_expression_over_column(
-        columns[0], glotexp.Coalesce, expressions=[col.expression for col in columns[1:]] if len(columns) > 1 else None
-    )
+    if len(cols) > 1:
+        return Column.invoke_expression_over_column(cols[0], glotexp.Coalesce, expressions=cols[1:])
+    return Column.invoke_expression_over_column(cols[0], glotexp.Coalesce)
 
 
 def corr(col1: ColumnOrName, col2: ColumnOrName) -> Column:
@@ -405,11 +401,13 @@ def nanvl(col1: ColumnOrName, col2: ColumnOrName) -> Column:
 def percentile_approx(
     col: ColumnOrName,
     percentage: t.Union[ColumnOrLiteral, t.List[float], t.Tuple[float]],
-    accuracy: t.Optional[t.Union[ColumnOrLiteral]] = None,
+    accuracy: t.Optional[t.Union[ColumnOrLiteral, int]] = None,
 ) -> Column:
     if accuracy:
-        return Column.invoke_anonymous_function(col, "PERCENTILE_APPROX", percentage, accuracy)
-    return Column.invoke_anonymous_function(col, "PERCENTILE_APPROX", percentage)
+        return Column.invoke_expression_over_column(
+            col, glotexp.ApproxQuantile, quantile=lit(percentage), accuracy=accuracy
+        )
+    return Column.invoke_expression_over_column(col, glotexp.ApproxQuantile, quantile=lit(percentage))
 
 
 def rand(seed: t.Optional[ColumnOrLiteral] = None) -> Column:
@@ -422,7 +420,7 @@ def randn(seed: t.Optional[ColumnOrLiteral] = None) -> Column:
 
 def round(col: ColumnOrName, scale: t.Optional[int] = None) -> Column:
     if scale is not None:
-        return Column.invoke_expression_over_column(col, glotexp.Round, decimals=glotexp.convert(scale))
+        return Column.invoke_expression_over_column(col, glotexp.Round, decimals=scale)
     return Column.invoke_expression_over_column(col, glotexp.Round)
 
 
@@ -433,9 +431,7 @@ def bround(col: ColumnOrName, scale: t.Optional[int] = None) -> Column:
 
 
 def shiftleft(col: ColumnOrName, numBits: int) -> Column:
-    return Column.invoke_expression_over_column(
-        col, glotexp.BitwiseLeftShift, expression=Column.ensure_col(numBits).expression
-    )
+    return Column.invoke_expression_over_column(col, glotexp.BitwiseLeftShift, expression=numBits)
 
 
 def shiftLeft(col: ColumnOrName, numBits: int) -> Column:
@@ -443,9 +439,7 @@ def shiftLeft(col: ColumnOrName, numBits: int) -> Column:
 
 
 def shiftright(col: ColumnOrName, numBits: int) -> Column:
-    return Column.invoke_expression_over_column(
-        col, glotexp.BitwiseRightShift, expression=Column.ensure_col(numBits).expression
-    )
+    return Column.invoke_expression_over_column(col, glotexp.BitwiseRightShift, expression=numBits)
 
 
 def shiftRight(col: ColumnOrName, numBits: int) -> Column:
@@ -466,8 +460,7 @@ def expr(str: str) -> Column:
 
 def struct(col: t.Union[ColumnOrName, t.Iterable[ColumnOrName]], *cols: ColumnOrName) -> Column:
     columns = ensure_list(col) + list(cols)
-    expressions = [Column.ensure_col(column).expression for column in columns]
-    return Column(glotexp.Struct(expressions=expressions))
+    return Column.invoke_expression_over_column(None, glotexp.Struct, expressions=columns)
 
 
 def conv(col: ColumnOrName, fromBase: int, toBase: int) -> Column:
@@ -515,7 +508,7 @@ def current_timestamp() -> Column:
 
 
 def date_format(col: ColumnOrName, format: str) -> Column:
-    return Column.invoke_anonymous_function(col, "DATE_FORMAT", lit(format))
+    return Column.invoke_expression_over_column(col, glotexp.TimeToStr, format=lit(format))
 
 
 def year(col: ColumnOrName) -> Column:
@@ -563,15 +556,15 @@ def make_date(year: ColumnOrName, month: ColumnOrName, day: ColumnOrName) -> Col
 
 
 def date_add(col: ColumnOrName, days: t.Union[ColumnOrName, int]) -> Column:
-    return Column.invoke_expression_over_column(col, glotexp.DateAdd, expression=Column.ensure_col(days).expression)
+    return Column.invoke_expression_over_column(col, glotexp.DateAdd, expression=days)
 
 
 def date_sub(col: ColumnOrName, days: t.Union[ColumnOrName, int]) -> Column:
-    return Column.invoke_expression_over_column(col, glotexp.DateSub, expression=Column.ensure_col(days).expression)
+    return Column.invoke_expression_over_column(col, glotexp.DateSub, expression=days)
 
 
 def date_diff(end: ColumnOrName, start: ColumnOrName) -> Column:
-    return Column.invoke_expression_over_column(end, glotexp.DateDiff, expression=Column.ensure_col(start).expression)
+    return Column.invoke_expression_over_column(end, glotexp.DateDiff, expression=start)
 
 
 def add_months(start: ColumnOrName, months: t.Union[ColumnOrName, int]) -> Column:
@@ -586,8 +579,8 @@ def months_between(date1: ColumnOrName, date2: ColumnOrName, roundOff: t.Optiona
 
 def to_date(col: ColumnOrName, format: t.Optional[str] = None) -> Column:
     if format is not None:
-        return Column.invoke_anonymous_function(col, "TO_DATE", lit(format))
-    return Column.invoke_anonymous_function(col, "TO_DATE")
+        return Column.invoke_expression_over_column(col, glotexp.TsOrDsToDate, format=lit(format))
+    return Column.invoke_expression_over_column(col, glotexp.TsOrDsToDate)
 
 
 def to_timestamp(col: ColumnOrName, format: t.Optional[str] = None) -> Column:
@@ -597,11 +590,11 @@ def to_timestamp(col: ColumnOrName, format: t.Optional[str] = None) -> Column:
 
 
 def trunc(col: ColumnOrName, format: str) -> Column:
-    return Column.invoke_expression_over_column(col, glotexp.DateTrunc, unit=lit(format).expression)
+    return Column.invoke_expression_over_column(col, glotexp.DateTrunc, unit=lit(format))
 
 
 def date_trunc(format: str, timestamp: ColumnOrName) -> Column:
-    return Column.invoke_expression_over_column(timestamp, glotexp.TimestampTrunc, unit=lit(format).expression)
+    return Column.invoke_expression_over_column(timestamp, glotexp.TimestampTrunc, unit=lit(format))
 
 
 def next_day(col: ColumnOrName, dayOfWeek: str) -> Column:
@@ -614,14 +607,14 @@ def last_day(col: ColumnOrName) -> Column:
 
 def from_unixtime(col: ColumnOrName, format: t.Optional[str] = None) -> Column:
     if format is not None:
-        return Column.invoke_anonymous_function(col, "FROM_UNIXTIME", lit(format))
-    return Column.invoke_anonymous_function(col, "FROM_UNIXTIME")
+        return Column.invoke_expression_over_column(col, glotexp.UnixToStr, format=lit(format))
+    return Column.invoke_expression_over_column(col, glotexp.UnixToStr)
 
 
 def unix_timestamp(timestamp: t.Optional[ColumnOrName] = None, format: t.Optional[str] = None) -> Column:
     if format is not None:
-        return Column.invoke_anonymous_function(timestamp, "UNIX_TIMESTAMP", lit(format))
-    return Column.invoke_anonymous_function(timestamp, "UNIX_TIMESTAMP")
+        return Column.invoke_expression_over_column(timestamp, glotexp.StrToUnix, format=lit(format))
+    return Column.invoke_expression_over_column(timestamp, glotexp.StrToUnix)
 
 
 def from_utc_timestamp(timestamp: ColumnOrName, tz: ColumnOrName) -> Column:
@@ -738,10 +731,7 @@ def trim(col: ColumnOrName) -> Column:
 
 
 def concat_ws(sep: str, *cols: ColumnOrName) -> Column:
-    columns = [Column(col) for col in cols]
-    return Column.invoke_expression_over_column(
-        None, glotexp.ConcatWs, expressions=[x.expression for x in [lit(sep)] + list(columns)]
-    )
+    return Column.invoke_expression_over_column(None, glotexp.ConcatWs, expressions=[lit(sep)] + list(cols))
 
 
 def decode(col: ColumnOrName, charset: str) -> Column:
@@ -798,18 +788,14 @@ def substring_index(str: ColumnOrName, delim: str, count: int) -> Column:
 
 
 def levenshtein(left: ColumnOrName, right: ColumnOrName) -> Column:
-    return Column.invoke_expression_over_column(
-        left, glotexp.Levenshtein, expression=Column.ensure_col(right).expression
-    )
+    return Column.invoke_expression_over_column(left, glotexp.Levenshtein, expression=right)
 
 
 def locate(substr: str, str: ColumnOrName, pos: t.Optional[int] = None) -> Column:
     substr_col = lit(substr)
-    pos_column = lit(pos)
-    str_column = Column.ensure_col(str)
     if pos is not None:
-        return Column.invoke_anonymous_function(substr_col, "LOCATE", str_column, pos_column)
-    return Column.invoke_anonymous_function(substr_col, "LOCATE", str_column)
+        return Column.invoke_expression_over_column(str, glotexp.StrPosition, substr=substr_col, position=pos)
+    return Column.invoke_expression_over_column(str, glotexp.StrPosition, substr=substr_col)
 
 
 def lpad(col: ColumnOrName, len: int, pad: str) -> Column:
@@ -821,15 +807,15 @@ def rpad(col: ColumnOrName, len: int, pad: str) -> Column:
 
 
 def repeat(col: ColumnOrName, n: int) -> Column:
-    return Column.invoke_anonymous_function(col, "REPEAT", n)
+    return Column.invoke_expression_over_column(col, glotexp.Repeat, times=lit(n))
 
 
 def split(str: ColumnOrName, pattern: str, limit: t.Optional[int] = None) -> Column:
     if limit is not None:
         return Column.invoke_expression_over_column(
-            str, glotexp.RegexpSplit, expression=lit(pattern).expression, limit=lit(limit).expression
+            str, glotexp.RegexpSplit, expression=lit(pattern).expression, limit=limit
         )
-    return Column.invoke_expression_over_column(str, glotexp.RegexpSplit, expression=lit(pattern).expression)
+    return Column.invoke_expression_over_column(str, glotexp.RegexpSplit, expression=lit(pattern))
 
 
 def regexp_extract(str: ColumnOrName, pattern: str, idx: t.Optional[int] = None) -> Column:
@@ -879,9 +865,8 @@ def translate(srcCol: ColumnOrName, matching: str, replace: str) -> Column:
 
 
 def array(*cols: t.Union[ColumnOrName, t.Iterable[ColumnOrName]]) -> Column:
-    cols = _flatten(cols) if not isinstance(cols[0], (str, Column)) else cols  # type: ignore
-    cols = [Column.ensure_col(col).expression for col in cols]  # type: ignore
-    return Column.invoke_expression_over_column(None, glotexp.Array, expressions=cols)
+    columns = _flatten(cols) if not isinstance(cols[0], (str, Column)) else cols
+    return Column.invoke_expression_over_column(None, glotexp.Array, expressions=columns)
 
 
 def create_map(*cols: t.Union[ColumnOrName, t.Iterable[ColumnOrName]]) -> Column:
@@ -892,7 +877,7 @@ def create_map(*cols: t.Union[ColumnOrName, t.Iterable[ColumnOrName]]) -> Column
 
 
 def map_from_arrays(col1: ColumnOrName, col2: ColumnOrName) -> Column:
-    return Column.invoke_anonymous_function(col1, "MAP_FROM_ARRAYS", col2)
+    return Column.invoke_expression_over_column(None, glotexp.Map, keys=col1, values=col2)
 
 
 def array_contains(col: ColumnOrName, value: ColumnOrLiteral) -> Column:
@@ -970,7 +955,7 @@ def posexplode_outer(col: ColumnOrName) -> Column:
 
 
 def get_json_object(col: ColumnOrName, path: str) -> Column:
-    return Column.invoke_expression_over_column(col, glotexp.JSONExtract, path=lit(path).expression)
+    return Column.invoke_expression_over_column(col, glotexp.JSONExtract, path=lit(path))
 
 
 def json_tuple(col: ColumnOrName, *fields: str) -> Column:
@@ -1031,11 +1016,17 @@ def array_max(col: ColumnOrName) -> Column:
 
 def sort_array(col: ColumnOrName, asc: t.Optional[bool] = None) -> Column:
     if asc is not None:
-        return Column.invoke_anonymous_function(col, "SORT_ARRAY", lit(asc))
-    return Column.invoke_anonymous_function(col, "SORT_ARRAY")
+        return Column.invoke_expression_over_column(col, glotexp.SortArray, asc=asc)
+    return Column.invoke_expression_over_column(col, glotexp.SortArray)
 
 
-def array_sort(col: ColumnOrName) -> Column:
+def array_sort(
+    col: ColumnOrName,
+    comparator: t.Optional[t.Union[t.Callable[[Column, Column], Column]]] = None,
+) -> Column:
+    if comparator is not None:
+        f_expression = _get_lambda_from_func(comparator)
+        return Column.invoke_expression_over_column(col, glotexp.ArraySort, expression=f_expression)
     return Column.invoke_expression_over_column(col, glotexp.ArraySort)
 
 
@@ -1108,130 +1099,53 @@ def aggregate(
     initialValue: ColumnOrName,
     merge: t.Callable[[Column, Column], Column],
     finish: t.Optional[t.Callable[[Column], Column]] = None,
-    accumulator_name: str = "acc",
-    target_row_name: str = "x",
 ) -> Column:
-    merge_exp = glotexp.Lambda(
-        this=merge(Column(accumulator_name), Column(target_row_name)).expression,
-        expressions=[
-            glotexp.to_identifier(accumulator_name, quoted=_lambda_quoted(accumulator_name)),
-            glotexp.to_identifier(target_row_name, quoted=_lambda_quoted(target_row_name)),
-        ],
-    )
+    merge_exp = _get_lambda_from_func(merge)
     if finish is not None:
-        finish_exp = glotexp.Lambda(
-            this=finish(Column(accumulator_name)).expression,
-            expressions=[glotexp.to_identifier(accumulator_name, quoted=_lambda_quoted(accumulator_name))],
-        )
+        finish_exp = _get_lambda_from_func(finish)
         return Column.invoke_anonymous_function(col, "AGGREGATE", initialValue, Column(merge_exp), Column(finish_exp))
     return Column.invoke_anonymous_function(col, "AGGREGATE", initialValue, Column(merge_exp))
 
 
 def transform(
-    col: ColumnOrName,
-    f: t.Union[t.Callable[[Column], Column], t.Callable[[Column, Column], Column]],
-    target_row_name: str = "x",
-    row_count_name: str = "i",
+    col: ColumnOrName, f: t.Union[t.Callable[[Column], Column], t.Callable[[Column, Column], Column]]
 ) -> Column:
-    num_arguments = len(signature(f).parameters)
-    expressions = [glotexp.to_identifier(target_row_name, quoted=_lambda_quoted(target_row_name))]
-    columns = [Column(target_row_name)]
-    if num_arguments > 1:
-        columns.append(Column(row_count_name))
-        expressions.append(glotexp.to_identifier(row_count_name, quoted=_lambda_quoted(row_count_name)))
-
-    f_expression = glotexp.Lambda(this=f(*columns).expression, expressions=expressions)
+    f_expression = _get_lambda_from_func(f)
     return Column.invoke_anonymous_function(col, "TRANSFORM", Column(f_expression))
 
 
-def exists(col: ColumnOrName, f: t.Callable[[Column], Column], target_row_name: str = "x") -> Column:
-    f_expression = glotexp.Lambda(
-        this=f(Column(target_row_name)).expression,
-        expressions=[glotexp.to_identifier(target_row_name, quoted=_lambda_quoted(target_row_name))],
-    )
+def exists(col: ColumnOrName, f: t.Callable[[Column], Column]) -> Column:
+    f_expression = _get_lambda_from_func(f)
     return Column.invoke_anonymous_function(col, "EXISTS", Column(f_expression))
 
 
-def forall(col: ColumnOrName, f: t.Callable[[Column], Column], target_row_name: str = "x") -> Column:
-    f_expression = glotexp.Lambda(
-        this=f(Column(target_row_name)).expression,
-        expressions=[glotexp.to_identifier(target_row_name, quoted=_lambda_quoted(target_row_name))],
-    )
-
+def forall(col: ColumnOrName, f: t.Callable[[Column], Column]) -> Column:
+    f_expression = _get_lambda_from_func(f)
     return Column.invoke_anonymous_function(col, "FORALL", Column(f_expression))
 
 
-def filter(
-    col: ColumnOrName,
-    f: t.Union[t.Callable[[Column], Column], t.Callable[[Column, Column], Column]],
-    target_row_name: str = "x",
-    row_count_name: str = "i",
-) -> Column:
-    num_arguments = len(signature(f).parameters)
-    expressions = [glotexp.to_identifier(target_row_name, quoted=_lambda_quoted(target_row_name))]
-    columns = [Column(target_row_name)]
-    if num_arguments > 1:
-        columns.append(Column(row_count_name))
-        expressions.append(glotexp.to_identifier(row_count_name, quoted=_lambda_quoted(row_count_name)))
-
-    f_expression = glotexp.Lambda(this=f(*columns).expression, expressions=expressions)
-    return Column.invoke_anonymous_function(col, "FILTER", Column(f_expression))
-
-
-def zip_with(
-    left: ColumnOrName,
-    right: ColumnOrName,
-    f: t.Callable[[Column, Column], Column],
-    left_name: str = "x",
-    right_name: str = "y",
-) -> Column:
-    f_expression = glotexp.Lambda(
-        this=f(Column(left_name), Column(right_name)).expression,
-        expressions=[
-            glotexp.to_identifier(left_name, quoted=_lambda_quoted(left_name)),
-            glotexp.to_identifier(right_name, quoted=_lambda_quoted(right_name)),
-        ],
-    )
+def filter(col: ColumnOrName, f: t.Union[t.Callable[[Column], Column], t.Callable[[Column, Column], Column]]) -> Column:
+    f_expression = _get_lambda_from_func(f)
+    return Column.invoke_expression_over_column(col, glotexp.ArrayFilter, expression=f_expression)
 
+
+def zip_with(left: ColumnOrName, right: ColumnOrName, f: t.Callable[[Column, Column], Column]) -> Column:
+    f_expression = _get_lambda_from_func(f)
     return Column.invoke_anonymous_function(left, "ZIP_WITH", right, Column(f_expression))
 
 
-def transform_keys(
-    col: ColumnOrName, f: t.Union[t.Callable[[Column, Column], Column]], key_name: str = "k", value_name: str = "v"
-) -> Column:
-    f_expression = glotexp.Lambda(
-        this=f(Column(key_name), Column(value_name)).expression,
-        expressions=[
-            glotexp.to_identifier(key_name, quoted=_lambda_quoted(key_name)),
-            glotexp.to_identifier(value_name, quoted=_lambda_quoted(value_name)),
-        ],
-    )
+def transform_keys(col: ColumnOrName, f: t.Union[t.Callable[[Column, Column], Column]]) -> Column:
+    f_expression = _get_lambda_from_func(f)
     return Column.invoke_anonymous_function(col, "TRANSFORM_KEYS", Column(f_expression))
 
 
-def transform_values(
-    col: ColumnOrName, f: t.Union[t.Callable[[Column, Column], Column]], key_name: str = "k", value_name: str = "v"
-) -> Column:
-    f_expression = glotexp.Lambda(
-        this=f(Column(key_name), Column(value_name)).expression,
-        expressions=[
-            glotexp.to_identifier(key_name, quoted=_lambda_quoted(key_name)),
-            glotexp.to_identifier(value_name, quoted=_lambda_quoted(value_name)),
-        ],
-    )
+def transform_values(col: ColumnOrName, f: t.Union[t.Callable[[Column, Column], Column]]) -> Column:
+    f_expression = _get_lambda_from_func(f)
     return Column.invoke_anonymous_function(col, "TRANSFORM_VALUES", Column(f_expression))
 
 
-def map_filter(
-    col: ColumnOrName, f: t.Union[t.Callable[[Column, Column], Column]], key_name: str = "k", value_name: str = "v"
-) -> Column:
-    f_expression = glotexp.Lambda(
-        this=f(Column(key_name), Column(value_name)).expression,
-        expressions=[
-            glotexp.to_identifier(key_name, quoted=_lambda_quoted(key_name)),
-            glotexp.to_identifier(value_name, quoted=_lambda_quoted(value_name)),
-        ],
-    )
+def map_filter(col: ColumnOrName, f: t.Union[t.Callable[[Column, Column], Column]]) -> Column:
+    f_expression = _get_lambda_from_func(f)
     return Column.invoke_anonymous_function(col, "MAP_FILTER", Column(f_expression))
 
 
@@ -1239,20 +1153,18 @@ def map_zip_with(
     col1: ColumnOrName,
     col2: ColumnOrName,
     f: t.Union[t.Callable[[Column, Column, Column], Column]],
-    key_name: str = "k",
-    value1: str = "v1",
-    value2: str = "v2",
 ) -> Column:
-    f_expression = glotexp.Lambda(
-        this=f(Column(key_name), Column(value1), Column(value2)).expression,
-        expressions=[
-            glotexp.to_identifier(key_name, quoted=_lambda_quoted(key_name)),
-            glotexp.to_identifier(value1, quoted=_lambda_quoted(value1)),
-            glotexp.to_identifier(value2, quoted=_lambda_quoted(value2)),
-        ],
-    )
+    f_expression = _get_lambda_from_func(f)
     return Column.invoke_anonymous_function(col1, "MAP_ZIP_WITH", col2, Column(f_expression))
 
 
 def _lambda_quoted(value: str) -> t.Optional[bool]:
     return False if value == "_" else None
+
+
+def _get_lambda_from_func(lambda_expression: t.Callable):
+    variables = [glotexp.to_identifier(x, quoted=_lambda_quoted(x)) for x in lambda_expression.__code__.co_varnames]
+    return glotexp.Lambda(
+        this=lambda_expression(*[Column(x) for x in variables]).expression,
+        expressions=variables,
+    )
diff --git a/sqlglot/dialects/hive.py b/sqlglot/dialects/hive.py
index 0810e0c..63fdb85 100644
--- a/sqlglot/dialects/hive.py
+++ b/sqlglot/dialects/hive.py
@@ -18,6 +18,36 @@ from sqlglot.helper import list_get
 from sqlglot.parser import Parser, parse_var_map
 from sqlglot.tokens import Tokenizer
 
+# (FuncType, Multiplier)
+DATE_DELTA_INTERVAL = {
+    "YEAR": ("ADD_MONTHS", 12),
+    "MONTH": ("ADD_MONTHS", 1),
+    "QUARTER": ("ADD_MONTHS", 3),
+    "WEEK": ("DATE_ADD", 7),
+    "DAY": ("DATE_ADD", 1),
+}
+
+DIFF_MONTH_SWITCH = ("YEAR", "QUARTER", "MONTH")
+
+
+def _add_date_sql(self, expression):
+    unit = expression.text("unit").upper()
+    func, multiplier = DATE_DELTA_INTERVAL.get(unit, ("DATE_ADD", 1))
+    modified_increment = (
+        int(expression.text("expression")) * multiplier if expression.expression.is_number else expression.expression
+    )
+    modified_increment = exp.Literal.number(modified_increment)
+    return f"{func}({self.format_args(expression.this, modified_increment.this)})"
+
+
+def _date_diff_sql(self, expression):
+    unit = expression.text("unit").upper()
+    sql_func = "MONTHS_BETWEEN" if unit in DIFF_MONTH_SWITCH else "DATEDIFF"
+    _, multiplier = DATE_DELTA_INTERVAL.get(unit, ("", 1))
+    multiplier_sql = f" / {multiplier}" if multiplier > 1 else ""
+    diff_sql = f"{sql_func}({self.format_args(expression.this, expression.expression)})"
+    return f"{diff_sql}{multiplier_sql}"
+
 
 def _array_sort(self, expression):
     if expression.expression:
@@ -120,10 +150,14 @@ class Hive(Dialect):
         "m": "%-M",
         "ss": "%S",
         "s": "%-S",
-        "S": "%f",
+        "SSSSSS": "%f",
         "a": "%p",
         "DD": "%j",
         "D": "%-j",
+        "E": "%a",
+        "EE": "%a",
+        "EEE": "%a",
+        "EEEE": "%A",
     }
 
     date_format = "'yyyy-MM-dd'"
@@ -207,8 +241,8 @@ class Hive(Dialect):
             exp.ArraySize: rename_func("SIZE"),
             exp.ArraySort: _array_sort,
             exp.With: no_recursive_cte_sql,
-            exp.DateAdd: lambda self, e: f"DATE_ADD({self.sql(e, 'this')}, {self.sql(e, 'expression')})",
-            exp.DateDiff: lambda self, e: f"DATEDIFF({self.sql(e, 'this')}, {self.sql(e, 'expression')})",
+            exp.DateAdd: _add_date_sql,
+            exp.DateDiff: _date_diff_sql,
             exp.DateStrToDate: rename_func("TO_DATE"),
             exp.DateToDi: lambda self, e: f"CAST(DATE_FORMAT({self.sql(e, 'this')}, {Hive.dateint_format}) AS INT)",
             exp.DiToDate: lambda self, e: f"TO_DATE(CAST({self.sql(e, 'this')} AS STRING), {Hive.dateint_format})",
diff --git a/sqlglot/dialects/spark.py b/sqlglot/dialects/spark.py
index 6bf4ff0..572f411 100644
--- a/sqlglot/dialects/spark.py
+++ b/sqlglot/dialects/spark.py
@@ -71,6 +71,7 @@ class Spark(Hive):
                 length=list_get(args, 1),
             ),
             "APPROX_PERCENTILE": exp.ApproxQuantile.from_arg_list,
+            "IIF": exp.If.from_arg_list,
         }
 
         FUNCTION_PARSERS = {
@@ -111,6 +112,7 @@ class Spark(Hive):
             exp.StructKwarg: lambda self, e: f"{self.sql(e, 'this')}: {self.sql(e, 'expression')}",
             exp.TimestampTrunc: lambda self, e: f"DATE_TRUNC({self.sql(e, 'unit')}, {self.sql(e, 'this')})",
             exp.VariancePop: rename_func("VAR_POP"),
+            exp.DateFromParts: rename_func("MAKE_DATE"),
         }
 
         WRAP_DERIVED_VALUES = False
diff --git a/sqlglot/dialects/starrocks.py b/sqlglot/dialects/starrocks.py
index ef8c82d..0cba6fe 100644
--- a/sqlglot/dialects/starrocks.py
+++ b/sqlglot/dialects/starrocks.py
@@ -1,5 +1,5 @@
 from sqlglot import exp
-from sqlglot.dialects.dialect import rename_func
+from sqlglot.dialects.dialect import arrow_json_extract_sql, rename_func
 from sqlglot.dialects.mysql import MySQL
 
 
@@ -14,6 +14,8 @@ class StarRocks(MySQL):
 
         TRANSFORMS = {
             **MySQL.Generator.TRANSFORMS,
+            exp.JSONExtractScalar: arrow_json_extract_sql,
+            exp.JSONExtract: arrow_json_extract_sql,
             exp.DateDiff: rename_func("DATEDIFF"),
             exp.StrToUnix: lambda self, e: f"UNIX_TIMESTAMP({self.sql(e, 'this')}, {self.format_time(e)})",
             exp.TimeStrToDate: rename_func("TO_DATE"),
diff --git a/sqlglot/dialects/tsql.py b/sqlglot/dialects/tsql.py
index 1f2e50d..107ace7 100644
--- a/sqlglot/dialects/tsql.py
+++ b/sqlglot/dialects/tsql.py
@@ -1,14 +1,149 @@
 from sqlglot import exp
-from sqlglot.dialects.dialect import Dialect
+from sqlglot.dialects.dialect import Dialect, rename_func
+from sqlglot.expressions import DataType
 from sqlglot.generator import Generator
+from sqlglot.helper import list_get
 from sqlglot.parser import Parser
+from sqlglot.time import format_time
 from sqlglot.tokens import Tokenizer, TokenType
 
+FULL_FORMAT_TIME_MAPPING = {"weekday": "%A", "dw": "%A", "w": "%A", "month": "%B", "mm": "%B", "m": "%B"}
+DATE_DELTA_INTERVAL = {
+    "year": "year",
+    "yyyy": "year",
+    "yy": "year",
+    "quarter": "quarter",
+    "qq": "quarter",
+    "q": "quarter",
+    "month": "month",
+    "mm": "month",
+    "m": "month",
+    "week": "week",
+    "ww": "week",
+    "wk": "week",
+    "day": "day",
+    "dd": "day",
+    "d": "day",
+}
+
+
+def tsql_format_time_lambda(exp_class, full_format_mapping=None, default=None):
+    def _format_time(args):
+        return exp_class(
+            this=list_get(args, 1),
+            format=exp.Literal.string(
+                format_time(
+                    list_get(args, 0).name or (TSQL.time_format if default is True else default),
+                    {**TSQL.time_mapping, **FULL_FORMAT_TIME_MAPPING} if full_format_mapping else TSQL.time_mapping,
+                )
+            ),
+        )
+
+    return _format_time
+
+
+def parse_date_delta(exp_class):
+    def inner_func(args):
+        unit = DATE_DELTA_INTERVAL.get(list_get(args, 0).name.lower(), "day")
+        return exp_class(this=list_get(args, 2), expression=list_get(args, 1), unit=unit)
+
+    return inner_func
+
+
+def generate_date_delta(self, e):
+    func = "DATEADD" if isinstance(e, exp.DateAdd) else "DATEDIFF"
+    return f"{func}({self.format_args(e.text('unit'), e.expression, e.this)})"
+
 
 class TSQL(Dialect):
     null_ordering = "nulls_are_small"
     time_format = "'yyyy-mm-dd hh:mm:ss'"
 
+    time_mapping = {
+        "yyyy": "%Y",
+        "yy": "%y",
+        "year": "%Y",
+        "qq": "%q",
+        "q": "%q",
+        "quarter": "%q",
+        "dayofyear": "%j",
+        "day": "%d",
+        "dy": "%d",
+        "y": "%Y",
+        "week": "%W",
+        "ww": "%W",
+        "wk": "%W",
+        "hour": "%h",
+        "hh": "%I",
+        "minute": "%M",
+        "mi": "%M",
+        "n": "%M",
+        "second": "%S",
+        "ss": "%S",
+        "s": "%-S",
+        "millisecond": "%f",
+        "ms": "%f",
+        "weekday": "%W",
+        "dw": "%W",
+        "month": "%m",
+        "mm": "%M",
+        "m": "%-M",
+        "Y": "%Y",
+        "YYYY": "%Y",
+        "YY": "%y",
+        "MMMM": "%B",
+        "MMM": "%b",
+        "MM": "%m",
+        "M": "%-m",
+        "dd": "%d",
+        "d": "%-d",
+        "HH": "%H",
+        "H": "%-H",
+        "h": "%-I",
+        "S": "%f",
+    }
+
+    convert_format_mapping = {
+        "0": "%b %d %Y %-I:%M%p",
+        "1": "%m/%d/%y",
+        "2": "%y.%m.%d",
+        "3": "%d/%m/%y",
+        "4": "%d.%m.%y",
+        "5": "%d-%m-%y",
+        "6": "%d %b %y",
+        "7": "%b %d, %y",
+        "8": "%H:%M:%S",
+        "9": "%b %d %Y %-I:%M:%S:%f%p",
+        "10": "mm-dd-yy",
+        "11": "yy/mm/dd",
+        "12": "yymmdd",
+        "13": "%d %b %Y %H:%M:ss:%f",
+        "14": "%H:%M:%S:%f",
+        "20": "%Y-%m-%d %H:%M:%S",
+        "21": "%Y-%m-%d %H:%M:%S.%f",
+        "22": "%m/%d/%y %-I:%M:%S %p",
+        "23": "%Y-%m-%d",
+        "24": "%H:%M:%S",
+        "25": "%Y-%m-%d %H:%M:%S.%f",
+        "100": "%b %d %Y %-I:%M%p",
+        "101": "%m/%d/%Y",
+        "102": "%Y.%m.%d",
+        "103": "%d/%m/%Y",
+        "104": "%d.%m.%Y",
+        "105": "%d-%m-%Y",
+        "106": "%d %b %Y",
+        "107": "%b %d, %Y",
+        "108": "%H:%M:%S",
+        "109": "%b %d %Y %-I:%M:%S:%f%p",
+        "110": "%m-%d-%Y",
+        "111": "%Y/%m/%d",
+        "112": "%Y%m%d",
+        "113": "%d %b %Y %H:%M:%S:%f",
+        "114": "%H:%M:%S:%f",
+        "120": "%Y-%m-%d %H:%M:%S",
+        "121": "%Y-%m-%d %H:%M:%S.%f",
+    }
+
     class Tokenizer(Tokenizer):
         IDENTIFIERS = ['"', ("[", "]")]
 
@@ -29,19 +164,67 @@ class TSQL(Dialect):
             "UNIQUEIDENTIFIER": TokenType.UNIQUEIDENTIFIER,
             "XML": TokenType.XML,
             "SQL_VARIANT": TokenType.VARIANT,
+            "NVARCHAR(MAX)": TokenType.TEXT,
+            "VARCHAR(MAX)": TokenType.TEXT,
         }
 
     class Parser(Parser):
         FUNCTIONS = {
             **Parser.FUNCTIONS,
             "CHARINDEX": exp.StrPosition.from_arg_list,
+            "ISNULL": exp.Coalesce.from_arg_list,
+            "DATEADD": parse_date_delta(exp.DateAdd),
+            "DATEDIFF": parse_date_delta(exp.DateDiff),
+            "DATENAME": tsql_format_time_lambda(exp.TimeToStr, full_format_mapping=True),
+            "DATEPART": tsql_format_time_lambda(exp.TimeToStr),
+            "GETDATE": exp.CurrentDate.from_arg_list,
+            "IIF": exp.If.from_arg_list,
+            "LEN": exp.Length.from_arg_list,
+            "REPLICATE": exp.Repeat.from_arg_list,
+            "JSON_VALUE": exp.JSONExtractScalar.from_arg_list,
+        }
+
+        VAR_LENGTH_DATATYPES = {
+            DataType.Type.NVARCHAR,
+            DataType.Type.VARCHAR,
+            DataType.Type.CHAR,
+            DataType.Type.NCHAR,
         }
 
-        def _parse_convert(self):
+        def _parse_convert(self, strict):
             to = self._parse_types()
             self._match(TokenType.COMMA)
             this = self._parse_field()
-            return self.expression(exp.Cast, this=this, to=to)
+
+            # Retrieve length of datatype and override to default if not specified
+            if list_get(to.expressions, 0) is None and to.this in self.VAR_LENGTH_DATATYPES:
+                to = exp.DataType.build(to.this, expressions=[exp.Literal.number(30)], nested=False)
+
+            # Check whether a conversion with format is applicable
+            if self._match(TokenType.COMMA):
+                format_val = self._parse_number().name
+                if format_val not in TSQL.convert_format_mapping:
+                    raise ValueError(f"CONVERT function at T-SQL does not support format style {format_val}")
+                format_norm = exp.Literal.string(TSQL.convert_format_mapping[format_val])
+
+                # Check whether the convert entails a string to date format
+                if to.this == DataType.Type.DATE:
+                    return self.expression(exp.StrToDate, this=this, format=format_norm)
+                # Check whether the convert entails a string to datetime format
+                elif to.this == DataType.Type.DATETIME:
+                    return self.expression(exp.StrToTime, this=this, format=format_norm)
+                # Check whether the convert entails a date to string format
+                elif to.this in self.VAR_LENGTH_DATATYPES:
+                    return self.expression(
+                        exp.Cast if strict else exp.TryCast,
+                        to=to,
+                        this=self.expression(exp.TimeToStr, this=this, format=format_norm),
+                    )
+                elif to.this == DataType.Type.TEXT:
+                    return self.expression(exp.TimeToStr, this=this, format=format_norm)
+
+            # Entails a simple cast without any format requirement
+            return self.expression(exp.Cast if strict else exp.TryCast, this=this, to=to)
 
     class Generator(Generator):
         TYPE_MAPPING = {
@@ -52,3 +235,11 @@ class TSQL(Dialect):
             exp.DataType.Type.DATETIME: "DATETIME2",
             exp.DataType.Type.VARIANT: "SQL_VARIANT",
         }
+
+        TRANSFORMS = {
+            **Generator.TRANSFORMS,
+            exp.DateAdd: lambda self, e: generate_date_delta(self, e),
+            exp.DateDiff: lambda self, e: generate_date_delta(self, e),
+            exp.CurrentDate: rename_func("GETDATE"),
+            exp.If: rename_func("IIF"),
+        }
diff --git a/sqlglot/expressions.py b/sqlglot/expressions.py
index f7717c8..eb7854a 100644
--- a/sqlglot/expressions.py
+++ b/sqlglot/expressions.py
@@ -2411,6 +2411,11 @@ class TimeTrunc(Func, TimeUnit):
     arg_types = {"this": True, "unit": True, "zone": False}
 
 
+class DateFromParts(Func):
+    _sql_names = ["DATEFROMPARTS"]
+    arg_types = {"year": True, "month": True, "day": True}
+
+
 class DateStrToDate(Func):
     pass
 
@@ -2554,7 +2559,7 @@ class Quantile(AggFunc):
 
 
 class ApproxQuantile(Quantile):
-    pass
+    arg_types = {"this": True, "quantile": True, "accuracy": False}
 
 
 class Reduce(Func):
@@ -2569,6 +2574,10 @@ class RegexpSplit(Func):
     arg_types = {"this": True, "expression": True}
 
 
+class Repeat(Func):
+    arg_types = {"this": True, "times": True}
+
+
 class Round(Func):
     arg_types = {"this": True, "decimals": False}
 
@@ -2690,7 +2699,7 @@ class TsOrDiToDi(Func):
 
 
 class UnixToStr(Func):
-    arg_types = {"this": True, "format": True}
+    arg_types = {"this": True, "format": False}
 
 
 class UnixToTime(Func):
@@ -3077,6 +3086,8 @@ def update(table, properties, where=None, from_=None, dialect=None, **opts):
     )
     if from_:
         update.set("from", maybe_parse(from_, into=From, dialect=dialect, prefix="FROM", **opts))
+    if isinstance(where, Condition):
+        where = Where(this=where)
     if where:
         update.set("where", maybe_parse(where, into=Where, dialect=dialect, prefix="WHERE", **opts))
     return update
@@ -3518,6 +3529,41 @@ def replace_tables(expression, mapping):
     return expression.transform(_replace_tables)
 
 
+def replace_placeholders(expression, *args, **kwargs):
+    """Replace placeholders in an expression.
+
+    Args:
+        expression (sqlglot.Expression): Expression node to be transformed and replaced
+        args: Positional names that will substitute unnamed placeholders in the given order
+        kwargs: Keyword arguments that will substitute named placeholders
+
+    Examples:
+        >>> from sqlglot import exp, parse_one
+        >>> replace_placeholders(
+        ...     parse_one("select * from :tbl where ? = ?"), "a", "b", tbl="foo"
+        ... ).sql()
+        'SELECT * FROM foo WHERE a = b'
+
+    Returns:
+        The mapped expression
+    """
+
+    def _replace_placeholders(node, args, **kwargs):
+        if isinstance(node, Placeholder):
+            if node.name:
+                new_name = kwargs.get(node.name)
+                if new_name:
+                    return to_identifier(new_name)
+            else:
+                try:
+                    return to_identifier(next(args))
+                except StopIteration:
+                    pass
+        return node
+
+    return expression.transform(_replace_placeholders, iter(args), **kwargs)
+
+
 TRUE = Boolean(this=True)
 FALSE = Boolean(this=False)
 NULL = Null()
diff --git a/sqlglot/generator.py b/sqlglot/generator.py
index 6decd16..1784287 100644
--- a/sqlglot/generator.py
+++ b/sqlglot/generator.py
@@ -47,7 +47,8 @@ class Generator:
             The default is on the smaller end because the length only represents a segment and not the true
             line length.
             Default: 80
-        annotations: Whether or not to show annotations in the SQL.
+        annotations: Whether or not to show annotations in the SQL when `pretty` is True.
+            Annotations can only be shown in pretty mode otherwise they may clobber resulting sql.
             Default: True
     """
 
@@ -280,7 +281,7 @@ class Generator:
         raise ValueError(f"Unsupported expression type {expression.__class__.__name__}")
 
     def annotation_sql(self, expression):
-        if self._annotations:
+        if self._annotations and self.pretty:
             return f"{self.sql(expression, 'expression')} # {expression.name}"
         return self.sql(expression, "expression")
 
diff --git a/sqlglot/helper.py b/sqlglot/helper.py
index c3a23d3..42965d1 100644
--- a/sqlglot/helper.py
+++ b/sqlglot/helper.py
@@ -194,6 +194,24 @@ def split_num_words(value: str, sep: str, min_num_words: int, fill_from_start: b
     return words + [None] * (min_num_words - len(words))
 
 
+def is_iterable(value: t.Any) -> bool:
+    """
+    Checks if the value is an iterable but does not include strings and bytes
+
+    Examples:
+        >>> is_iterable([1,2])
+        True
+        >>> is_iterable("test")
+        False
+
+    Args:
+        value: The value to check if it is an interable
+
+    Returns: Bool indicating if it is an iterable
+    """
+    return hasattr(value, "__iter__") and not isinstance(value, (str, bytes))
+
+
 def flatten(values: t.Iterable[t.Union[t.Iterable[t.Any], t.Any]]) -> t.Generator[t.Any, None, None]:
     """
     Flattens a list that can contain both iterables and non-iterable elements
@@ -211,7 +229,7 @@ def flatten(values: t.Iterable[t.Union[t.Iterable[t.Any], t.Any]]) -> t.Generato
         Yields non-iterable elements (not including str or byte as iterable)
     """
     for value in values:
-        if hasattr(value, "__iter__") and not isinstance(value, (str, bytes)):
+        if is_iterable(value):
             yield from flatten(value)
         else:
             yield value
diff --git a/sqlglot/parser.py b/sqlglot/parser.py
index 47c1c1d..b94313a 100644
--- a/sqlglot/parser.py
+++ b/sqlglot/parser.py
@@ -433,7 +433,8 @@ class Parser:
     }
 
     FUNCTION_PARSERS = {
-        "CONVERT": lambda self: self._parse_convert(),
+        "CONVERT": lambda self: self._parse_convert(self.STRICT_CAST),
+        "TRY_CONVERT": lambda self: self._parse_convert(False),
         "EXTRACT": lambda self: self._parse_extract(),
         "POSITION": lambda self: self._parse_position(),
         "SUBSTRING": lambda self: self._parse_substring(),
@@ -1512,7 +1513,7 @@ class Parser:
         return this
 
     def _parse_offset(self, this=None):
-        if not self._match(TokenType.OFFSET):
+        if not self._match_set((TokenType.OFFSET, TokenType.COMMA)):
             return this
         count = self._parse_number()
         self._match_set((TokenType.ROW, TokenType.ROWS))
@@ -2134,7 +2135,7 @@ class Parser:
 
         return self.expression(exp.Cast if strict else exp.TryCast, this=this, to=to)
 
-    def _parse_convert(self):
+    def _parse_convert(self, strict):
         this = self._parse_field()
         if self._match(TokenType.USING):
             to = self.expression(exp.CharacterSet, this=self._parse_var())
@@ -2142,7 +2143,7 @@ class Parser:
             to = self._parse_types()
         else:
             to = None
-        return self.expression(exp.Cast, this=this, to=to)
+        return self.expression(exp.Cast if strict else exp.TryCast, this=this, to=to)
 
     def _parse_position(self):
         args = self._parse_csv(self._parse_bitwise)
diff --git a/sqlglot/time.py b/sqlglot/time.py
index 16314c5..de28ac0 100644
--- a/sqlglot/time.py
+++ b/sqlglot/time.py
@@ -14,6 +14,8 @@ def format_time(string, mapping, trie=None):
     mapping: Dictionary of time format to target time format
     trie: Optional trie, can be passed in for performance
     """
+    if not string:
+        return None
     start = 0
     end = 1
     size = len(string)