feat: add support for where clause as a sql expression

sqlframe/base/dataframe.py

@@ -606,8 +606,11 @@ def alias(self, name: str, **kwargs) -> Self:
         return df._convert_leaf_to_cte(sequence_id=new_sequence_id)
 
     @operation(Operation.WHERE)
-    def where(self, column: t.Union[Column, bool], **kwargs) -> Self:
-        col = self._ensure_and_normalize_col(column)
+    def where(self, column: t.Union[Column, str, bool], **kwargs) -> Self:
+        if isinstance(column, str):
+            col = sqlglot.parse_one(column, dialect=self.session.input_dialect)
+        else:
+            col = self._ensure_and_normalize_col(column)
         return self.copy(expression=self.expression.where(col.expression))
 
     filter = where

tests/integration/test_int_dataframe.py

@@ -302,6 +302,17 @@ def test_where_multiple_chained(
     compare_frames(df_employee, dfs_employee)
 
 
+def test_where_sql_expr(
+    pyspark_employee: PySparkDataFrame,
+    get_df: t.Callable[[str], _BaseDataFrame],
+    compare_frames: t.Callable,
+):
+    employee = get_df("employee")
+    df_employee = pyspark_employee.where("age = 37 AND fname = 'Jack'")
+    dfs_employee = employee.where("age = 37 AND fname = 'Jack'")
+    compare_frames(df_employee, dfs_employee)
+
+
 def test_operators(
     pyspark_employee: PySparkDataFrame,
     get_df: t.Callable[[str], _BaseDataFrame],