1 files changed, 32 insertions, 0 deletions
diff --git a/sqlglot/dataframe/sql/util.py b/sqlglot/dataframe/sql/util.py
new file mode 100644
index 0000000..575d18a
--- /dev/null
+++ b/sqlglot/dataframe/sql/util.py
@@ -0,0 +1,32 @@
+from __future__ import annotations
+
+import typing as t
+
+from sqlglot import expressions as exp
+from sqlglot.dataframe.sql import types
+
+if t.TYPE_CHECKING:
+    from sqlglot.dataframe.sql._typing import SchemaInput
+
+
+def get_column_mapping_from_schema_input(schema: SchemaInput) -> t.Dict[str, t.Optional[str]]:
+    if isinstance(schema, dict):
+        return schema
+    elif isinstance(schema, str):
+        col_name_type_strs = [x.strip() for x in schema.split(",")]
+        return {
+            name_type_str.split(":")[0].strip(): name_type_str.split(":")[1].strip()
+            for name_type_str in col_name_type_strs
+        }
+    elif isinstance(schema, types.StructType):
+        return {struct_field.name: struct_field.dataType.simpleString() for struct_field in schema}
+    return {x.strip(): None for x in schema}  # type: ignore
+
+
+def get_tables_from_expression_with_join(expression: exp.Select) -> t.List[exp.Table]:
+    if not expression.args.get("joins"):
+        return []
+
+    left_table = expression.args["from"].args["expressions"][0]
+    other_tables = [join.this for join in expression.args["joins"]]
+    return [left_table] + other_tables