1 files changed, 145 insertions, 0 deletions
diff --git a/sqlglot/dialects/snowflake.py b/sqlglot/dialects/snowflake.py
new file mode 100644
index 0000000..148dfb5
--- /dev/null
+++ b/sqlglot/dialects/snowflake.py
@@ -0,0 +1,145 @@
+from sqlglot import exp
+from sqlglot.dialects.dialect import Dialect, format_time_lambda, rename_func
+from sqlglot.expressions import Literal
+from sqlglot.generator import Generator
+from sqlglot.helper import list_get
+from sqlglot.parser import Parser
+from sqlglot.tokens import Tokenizer, TokenType
+
+
+def _check_int(s):
+    if s[0] in ("-", "+"):
+        return s[1:].isdigit()
+    return s.isdigit()
+
+
+# from https://docs.snowflake.com/en/sql-reference/functions/to_timestamp.html
+def _snowflake_to_timestamp(args):
+    if len(args) == 2:
+        first_arg, second_arg = args
+        if second_arg.is_string:
+            # case: <string_expr> [ , <format> ]
+            return format_time_lambda(exp.StrToTime, "snowflake")(args)
+
+        # case: <numeric_expr> [ , <scale> ]
+        if second_arg.name not in ["0", "3", "9"]:
+            raise ValueError(
+                f"Scale for snowflake numeric timestamp is {second_arg}, but should be 0, 3, or 9"
+            )
+
+        if second_arg.name == "0":
+            timescale = exp.UnixToTime.SECONDS
+        elif second_arg.name == "3":
+            timescale = exp.UnixToTime.MILLIS
+        elif second_arg.name == "9":
+            timescale = exp.UnixToTime.MICROS
+
+        return exp.UnixToTime(this=first_arg, scale=timescale)
+
+    first_arg = list_get(args, 0)
+    if not isinstance(first_arg, Literal):
+        # case: <variant_expr>
+        return format_time_lambda(exp.StrToTime, "snowflake", default=True)(args)
+
+    if first_arg.is_string:
+        if _check_int(first_arg.this):
+            # case: <integer>
+            return exp.UnixToTime.from_arg_list(args)
+
+        # case: <date_expr>
+        return format_time_lambda(exp.StrToTime, "snowflake", default=True)(args)
+
+    # case: <numeric_expr>
+    return exp.UnixToTime.from_arg_list(args)
+
+
+def _unix_to_time(self, expression):
+    scale = expression.args.get("scale")
+    timestamp = self.sql(expression, "this")
+    if scale in [None, exp.UnixToTime.SECONDS]:
+        return f"TO_TIMESTAMP({timestamp})"
+    if scale == exp.UnixToTime.MILLIS:
+        return f"TO_TIMESTAMP({timestamp}, 3)"
+    if scale == exp.UnixToTime.MICROS:
+        return f"TO_TIMESTAMP({timestamp}, 9)"
+
+    raise ValueError("Improper scale for timestamp")
+
+
+class Snowflake(Dialect):
+    null_ordering = "nulls_are_large"
+    time_format = "'yyyy-mm-dd hh24:mi:ss'"
+
+    time_mapping = {
+        "YYYY": "%Y",
+        "yyyy": "%Y",
+        "YY": "%y",
+        "yy": "%y",
+        "MMMM": "%B",
+        "mmmm": "%B",
+        "MON": "%b",
+        "mon": "%b",
+        "MM": "%m",
+        "mm": "%m",
+        "DD": "%d",
+        "dd": "%d",
+        "d": "%-d",
+        "DY": "%w",
+        "dy": "%w",
+        "HH24": "%H",
+        "hh24": "%H",
+        "HH12": "%I",
+        "hh12": "%I",
+        "MI": "%M",
+        "mi": "%M",
+        "SS": "%S",
+        "ss": "%S",
+        "FF": "%f",
+        "ff": "%f",
+        "FF6": "%f",
+        "ff6": "%f",
+    }
+
+    class Parser(Parser):
+        FUNCTIONS = {
+            **Parser.FUNCTIONS,
+            "ARRAYAGG": exp.ArrayAgg.from_arg_list,
+            "IFF": exp.If.from_arg_list,
+            "TO_TIMESTAMP": _snowflake_to_timestamp,
+        }
+
+        COLUMN_OPERATORS = {
+            **Parser.COLUMN_OPERATORS,
+            TokenType.COLON: lambda self, this, path: self.expression(
+                exp.Bracket,
+                this=this,
+                expressions=[path],
+            ),
+        }
+
+    class Tokenizer(Tokenizer):
+        QUOTES = ["'", "$$"]
+        ESCAPE = "\\"
+        KEYWORDS = {
+            **Tokenizer.KEYWORDS,
+            "QUALIFY": TokenType.QUALIFY,
+            "DOUBLE PRECISION": TokenType.DOUBLE,
+        }
+
+    class Generator(Generator):
+        TRANSFORMS = {
+            **Generator.TRANSFORMS,
+            exp.If: rename_func("IFF"),
+            exp.StrToTime: lambda self, e: f"TO_TIMESTAMP({self.sql(e, 'this')}, {self.format_time(e)})",
+            exp.UnixToTime: _unix_to_time,
+        }
+
+        def except_op(self, expression):
+            if not expression.args.get("distinct", False):
+                self.unsupported("EXCEPT with All is not supported in Snowflake")
+            return super().except_op(expression)
+
+        def intersect_op(self, expression):
+            if not expression.args.get("distinct", False):
+                self.unsupported("INTERSECT with All is not supported in Snowflake")
+            return super().intersect_op(expression)