1 files changed, 73 insertions, 0 deletions
diff --git a/sqlglot/dialects/redshift.py b/sqlglot/dialects/redshift.py
index 27dfb93..afd7913 100644
--- a/sqlglot/dialects/redshift.py
+++ b/sqlglot/dialects/redshift.py
@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+import typing as t
+
 from sqlglot import exp, transforms
 from sqlglot.dialects.dialect import rename_func
 from sqlglot.dialects.postgres import Postgres
@@ -21,6 +23,19 @@ class Redshift(Postgres):
             "NVL": exp.Coalesce.from_arg_list,
         }
 
+        def _parse_types(self, check_func: bool = False) -> t.Optional[exp.Expression]:
+            this = super()._parse_types(check_func=check_func)
+
+            if (
+                isinstance(this, exp.DataType)
+                and this.this == exp.DataType.Type.VARCHAR
+                and this.expressions
+                and this.expressions[0] == exp.column("MAX")
+            ):
+                this.set("expressions", [exp.Var(this="MAX")])
+
+            return this
+
     class Tokenizer(Postgres.Tokenizer):
         ESCAPES = ["\\"]
 
@@ -52,6 +67,10 @@ class Redshift(Postgres):
             exp.DistStyleProperty,
         }
 
+        WITH_PROPERTIES = {
+            exp.LikeProperty,
+        }
+
         TRANSFORMS = {
             **Postgres.Generator.TRANSFORMS,  # type: ignore
             **transforms.ELIMINATE_DISTINCT_ON,  # type: ignore
@@ -60,3 +79,57 @@ class Redshift(Postgres):
             exp.DistStyleProperty: lambda self, e: self.naked_property(e),
             exp.Matches: rename_func("DECODE"),
         }
+
+        def values_sql(self, expression: exp.Values) -> str:
+            """
+            Converts `VALUES...` expression into a series of unions.
+
+            Note: If you have a lot of unions then this will result in a large number of recursive statements to
+            evaluate the expression. You may need to increase `sys.setrecursionlimit` to run and it can also be
+            very slow.
+            """
+            if not isinstance(expression.unnest().parent, exp.From):
+                return super().values_sql(expression)
+            rows = [tuple_exp.expressions for tuple_exp in expression.expressions]
+            selects = []
+            for i, row in enumerate(rows):
+                if i == 0:
+                    row = [
+                        exp.alias_(value, column_name)
+                        for value, column_name in zip(row, expression.args["alias"].args["columns"])
+                    ]
+                selects.append(exp.Select(expressions=row))
+            subquery_expression = selects[0]
+            if len(selects) > 1:
+                for select in selects[1:]:
+                    subquery_expression = exp.union(subquery_expression, select, distinct=False)
+            return self.subquery_sql(subquery_expression.subquery(expression.alias))
+
+        def with_properties(self, properties: exp.Properties) -> str:
+            """Redshift doesn't have `WITH` as part of their with_properties so we remove it"""
+            return self.properties(properties, prefix=" ", suffix="")
+
+        def renametable_sql(self, expression: exp.RenameTable) -> str:
+            """Redshift only supports defining the table name itself (not the db) when renaming tables"""
+            expression = expression.copy()
+            target_table = expression.this
+            for arg in target_table.args:
+                if arg != "this":
+                    target_table.set(arg, None)
+            this = self.sql(expression, "this")
+            return f"RENAME TO {this}"
+
+        def datatype_sql(self, expression: exp.DataType) -> str:
+            """
+            Redshift converts the `TEXT` data type to `VARCHAR(255)` by default when people more generally mean
+            VARCHAR of max length which is `VARCHAR(max)` in Redshift. Therefore if we get a `TEXT` data type
+            without precision we convert it to `VARCHAR(max)` and if it does have precision then we just convert
+            `TEXT` to `VARCHAR`.
+            """
+            if expression.this == exp.DataType.Type.TEXT:
+                expression = expression.copy()
+                expression.set("this", exp.DataType.Type.VARCHAR)
+                precision = expression.args.get("expressions")
+                if not precision:
+                    expression.append("expressions", exp.Var(this="MAX"))
+            return super().datatype_sql(expression)