diff options
Diffstat (limited to 'sqlglot/dialects/redshift.py')
-rw-r--r-- | sqlglot/dialects/redshift.py | 73 |
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) |