Added initial fix for date type mismatch

Author: rajagurunath

dask_sql/mappings.py

@@ -163,7 +163,8 @@ def sql_to_python_value(sql_type: str, literal_value: Any) -> Any:
         dt = datetime.fromtimestamp(
             int(literal_value.getTimeInMillis()) / 1000, timezone.utc
         )
-
+        if sql_type == "DATE":
+            return dt.date()
         return dt
 
     elif sql_type.startswith("DECIMAL("):

dask_sql/physical/rex/core/call.py

@@ -196,14 +196,16 @@ def cast(self, operand, rex=None) -> SeriesOrScalar:
         if not is_frame(operand):
             return operand
 
-        output_type = str(rex.getType())
-        output_type = sql_to_python_type(output_type.upper())
-
-        return_column = cast_column_to_type(operand, output_type)
+        sql_output_type = str(rex.getType())
+        python_output_type = sql_to_python_type(sql_output_type.upper())
+        return_column = cast_column_to_type(operand, python_output_type)
 
         if return_column is None:
             return operand
         else:
+            # handle datetime type specially
+            if sql_output_type == "DATE":
+                return_column = return_column.dt.date
             return return_column
 
 

tests/integration/test_filter.py

@@ -68,3 +68,14 @@ def test_string_filter(c, string_table):
     assert_frame_equal(
         return_df, string_table.head(1),
     )
+
+
+def test_datetime_filter(c):
+    df = pd.DataFrame(
+        {"d_date": ["2001-08-01", "2001-08-02", "2001-08-03"], "val": [1, 2, 3]}
+    )
+    c.create_table("datetime_tbl1", df)
+    query = "SELECT val, d_date FROM datetime_tbl1 WHERE CAST(d_date as date) IN (date '2001-08-01', date '2001-08-03')"
+    result_df = c.sql(query).compute().reset_index(drop=True)
+    expected_df = pd.DataFrame({"val": [1, 3], "d_date": ["2001-08-01", "2001-08-03"]})
+    assert_frame_equal(result_df, expected_df, check_dtype=False)

tests/integration/test_select.py

@@ -115,3 +115,13 @@ def test_timezones(c, datetime_table):
     result_df = result_df.compute()
 
     assert_frame_equal(result_df, datetime_table)
+
+
+def test_date_casting(c, datetime_table):
+    # check date casting
+    query = "SELECT cast(timezone as date) as date1,cast(utc_timezone as date) as date2 FROM datetime_table "
+    result_df = c.sql(query).compute().astype(str)
+    expected_df = pd.DataFrame(
+        {"date1": ["2014-08-01"] * 3, "date2": ["2014-08-01"] * 3}
+    )
+    assert_frame_equal(result_df, expected_df, check_dtype=False)