1 files changed, 128 insertions, 0 deletions
diff --git a/sqlglot/dialects/bigquery.py b/sqlglot/dialects/bigquery.py
new file mode 100644
index 0000000..f4e87c3
--- /dev/null
+++ b/sqlglot/dialects/bigquery.py
@@ -0,0 +1,128 @@
+from sqlglot import exp
+from sqlglot.dialects.dialect import (
+    Dialect,
+    inline_array_sql,
+    no_ilike_sql,
+    rename_func,
+)
+from sqlglot.generator import Generator
+from sqlglot.helper import list_get
+from sqlglot.parser import Parser
+from sqlglot.tokens import Tokenizer, TokenType
+
+
+def _date_add(expression_class):
+    def func(args):
+        interval = list_get(args, 1)
+        return expression_class(
+            this=list_get(args, 0),
+            expression=interval.this,
+            unit=interval.args.get("unit"),
+        )
+
+    return func
+
+
+def _date_add_sql(data_type, kind):
+    def func(self, expression):
+        this = self.sql(expression, "this")
+        unit = self.sql(expression, "unit") or "'day'"
+        expression = self.sql(expression, "expression")
+        return f"{data_type}_{kind}({this}, INTERVAL {expression} {unit})"
+
+    return func
+
+
+class BigQuery(Dialect):
+    unnest_column_only = True
+
+    class Tokenizer(Tokenizer):
+        QUOTES = [
+            (prefix + quote, quote) if prefix else quote
+            for quote in ["'", '"', '"""', "'''"]
+            for prefix in ["", "r", "R"]
+        ]
+        IDENTIFIERS = ["`"]
+        ESCAPE = "\\"
+
+        KEYWORDS = {
+            **Tokenizer.KEYWORDS,
+            "CURRENT_DATETIME": TokenType.CURRENT_DATETIME,
+            "CURRENT_TIME": TokenType.CURRENT_TIME,
+            "GEOGRAPHY": TokenType.GEOGRAPHY,
+            "INT64": TokenType.BIGINT,
+            "FLOAT64": TokenType.DOUBLE,
+            "QUALIFY": TokenType.QUALIFY,
+            "UNKNOWN": TokenType.NULL,
+            "WINDOW": TokenType.WINDOW,
+        }
+
+    class Parser(Parser):
+        FUNCTIONS = {
+            **Parser.FUNCTIONS,
+            "DATE_ADD": _date_add(exp.DateAdd),
+            "DATETIME_ADD": _date_add(exp.DatetimeAdd),
+            "TIME_ADD": _date_add(exp.TimeAdd),
+            "TIMESTAMP_ADD": _date_add(exp.TimestampAdd),
+            "DATE_SUB": _date_add(exp.DateSub),
+            "DATETIME_SUB": _date_add(exp.DatetimeSub),
+            "TIME_SUB": _date_add(exp.TimeSub),
+            "TIMESTAMP_SUB": _date_add(exp.TimestampSub),
+        }
+
+        NO_PAREN_FUNCTIONS = {
+            **Parser.NO_PAREN_FUNCTIONS,
+            TokenType.CURRENT_DATETIME: exp.CurrentDatetime,
+            TokenType.CURRENT_TIME: exp.CurrentTime,
+        }
+
+    class Generator(Generator):
+        TRANSFORMS = {
+            exp.Array: inline_array_sql,
+            exp.ArraySize: rename_func("ARRAY_LENGTH"),
+            exp.DateAdd: _date_add_sql("DATE", "ADD"),
+            exp.DateSub: _date_add_sql("DATE", "SUB"),
+            exp.DatetimeAdd: _date_add_sql("DATETIME", "ADD"),
+            exp.DatetimeSub: _date_add_sql("DATETIME", "SUB"),
+            exp.ILike: no_ilike_sql,
+            exp.TimeAdd: _date_add_sql("TIME", "ADD"),
+            exp.TimeSub: _date_add_sql("TIME", "SUB"),
+            exp.TimestampAdd: _date_add_sql("TIMESTAMP", "ADD"),
+            exp.TimestampSub: _date_add_sql("TIMESTAMP", "SUB"),
+            exp.VariancePop: rename_func("VAR_POP"),
+        }
+
+        TYPE_MAPPING = {
+            **Generator.TYPE_MAPPING,
+            exp.DataType.Type.TINYINT: "INT64",
+            exp.DataType.Type.SMALLINT: "INT64",
+            exp.DataType.Type.INT: "INT64",
+            exp.DataType.Type.BIGINT: "INT64",
+            exp.DataType.Type.DECIMAL: "NUMERIC",
+            exp.DataType.Type.FLOAT: "FLOAT64",
+            exp.DataType.Type.DOUBLE: "FLOAT64",
+            exp.DataType.Type.BOOLEAN: "BOOL",
+            exp.DataType.Type.TEXT: "STRING",
+            exp.DataType.Type.VARCHAR: "STRING",
+            exp.DataType.Type.NVARCHAR: "STRING",
+        }
+
+        def in_unnest_op(self, unnest):
+            return self.sql(unnest)
+
+        def union_op(self, expression):
+            return f"UNION{' DISTINCT' if expression.args.get('distinct') else ' ALL'}"
+
+        def except_op(self, expression):
+            if not expression.args.get("distinct", False):
+                self.unsupported("EXCEPT without DISTINCT is not supported in BigQuery")
+            return f"EXCEPT{' DISTINCT' if expression.args.get('distinct') else ' ALL'}"
+
+        def intersect_op(self, expression):
+            if not expression.args.get("distinct", False):
+                self.unsupported(
+                    "INTERSECT without DISTINCT is not supported in BigQuery"
+                )
+            return (
+                f"INTERSECT{' DISTINCT' if expression.args.get('distinct') else ' ALL'}"
+            )