diff --git a/focus_validator/rules/checks.py b/focus_validator/rules/checks.py
index 58a9497..5a00e08 100644
--- a/focus_validator/rules/checks.py
+++ b/focus_validator/rules/checks.py
@@ -60,16 +60,14 @@ def check_sql_query(df_groups, sql_query, column_alias):
 
         # for the given indexes in false_indexes list, we are extracting the rows from the dataframe and
         # add column_alias value to failure_case column and index to index column
-        failure_cases = df[df.index.isin(false_indexes)]
-        failure_cases["failure_case"] = df.apply(
-            lambda row: {column: row[column] for column in column_alias}, axis=1
-        )
-        failure_cases["failure_case"] = df.apply(
-            lambda row: ",".join(
-                [f"{column}:{row[column]}" for column in column_alias]
-            ),
-            axis=1,
+        failure_cases = df[df.index.isin(false_indexes)].copy()
+        error_values = list(
+            [
+                ",".join([f"{column}:{row[column]}" for column in column_alias])
+                for _, row in failure_cases.iterrows()
+            ]
         )
+        failure_cases.loc[:, "failure_case"] = error_values
 
         raise SchemaError(
             schema=pa.DataFrameSchema(),
diff --git a/tests/data_loaders/test_null_value_loader.py b/tests/data_loaders/test_null_value_loader.py
index b45c9a7..ecd0670 100644
--- a/tests/data_loaders/test_null_value_loader.py
+++ b/tests/data_loaders/test_null_value_loader.py
@@ -27,7 +27,7 @@ def test_null_value_from_csv_with_missing_value(self):
         sample_data = pd.DataFrame([{"value": None}])
 
         buffer = io.BytesIO()
-        sample_data.to_csv(buffer, index=False)
+        sample_data.to_csv(buffer, index=False, lineterminator="\n")
 
         buffer.seek(0)
         self.assertEqual(buffer.read(), b'value\n""\n')