generates literal from None

Author: chelsea-lin

bigframes/bigquery/_operations/sql.py

@@ -74,7 +74,7 @@ def sql_scalar(
     # template, then this will fail with an error earlier in the process,
     # aiding users in debugging.
     literals_sql = [
-        sqlglot_ir._literal(column.values[0], column.dtype).sql(dialect="bigquery")
+        sqlglot_ir._literal(None, column.dtype).sql(dialect="bigquery")
         for column in columns
     ]
     select_sql = sql_template.format(*literals_sql)

tests/system/small/bigquery/test_sql.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import pytest
 import pandas as pd
 import pyarrow as pa
 
@@ -55,10 +56,26 @@ def test_sql_scalar_on_scalars_null_index(scalars_df_null_index):
     assert len(result) == len(scalars_df_null_index)
 
 
-def test_sql_scalar_w_bool_series(scalars_df_index):
-    series: bpd.Series = scalars_df_index["bool_col"]
-    result = bbq.sql_scalar("CAST({0} AS INT64)", [series])
-    expected = series.astype(dtypes.INT_DTYPE)
+@pytest.mark.parametrize(
+    ("column_name"),
+    [
+        pytest.param("bool_col"),
+        pytest.param("bytes_col"),
+        pytest.param("date_col"),
+        pytest.param("datetime_col"),
+        pytest.param("geography_col"),
+        pytest.param("int64_col"),
+        pytest.param("numeric_col"),
+        pytest.param("float64_col"),
+        pytest.param("string_col"),
+        pytest.param("time_col"),
+        pytest.param("timestamp_col"),
+    ],
+)
+def test_sql_scalar_w_all_scalar_output(scalars_df_index, column_name):
+    series: bpd.Series = scalars_df_index[column_name]
+    result = bbq.sql_scalar("{0}", [series])
+    expected = series
     expected.name = None
     pd.testing.assert_series_equal(result.to_pandas(), expected.to_pandas())