diff --git a/cmd/loadjson/main.go b/cmd/loadjson/main.go
index 5c370f03..2331176d 100644
--- a/cmd/loadjson/main.go
+++ b/cmd/loadjson/main.go
@@ -147,9 +147,11 @@ func processFile(ctx context.Context, path string) {
 	// Note that this step can succeed with any valid JSON file. But we need to do some additional validation to skip
 	// invalid query JSON files.
 	if unmarshalErr := json.Unmarshal(bytes, queryInfo); unmarshalErr != nil {
+		log.Error().Err(unmarshalErr).Str("path", path).Msg("failed to unmarshal JSON")
 		return
 	}
 	if queryInfo.QueryId == "" || queryInfo.QueryStats == nil || queryInfo.QueryStats.CreateTime == nil {
+		log.Error().Msg("QueryId, QueryStats or QueryStats.CreateTime is empty")
 		return
 	}
 	log.Info().Str("path", path).Msg("start to process file")
diff --git a/utils/orm.go b/utils/orm.go
index 8e2a9787..85eb8978 100644
--- a/utils/orm.go
+++ b/utils/orm.go
@@ -49,13 +49,16 @@ func SqlInsertObject(ctx context.Context, db *sql.DB, obj any, tableNames ...Tab
 		if len(rows) == 0 {
 			continue
 		}
-		placeholders := strings.Repeat("?,", rows[0].ColumnCount())
-		// Get rid of the trailing comma.
-		placeholders = placeholders[:len(placeholders)-1]
-		sqlStmt := fmt.Sprintf("INSERT INTO %s (%s) VALUES (%s)",
-			table, strings.Join(rows[0].ColumnNames, ","), placeholders)
+		if len(rows) == 1 && rows[0].ColumnCount() <= 1 {
+			continue
+		}
 
 		for _, row := range rows {
+			placeholders := strings.Repeat("?,", row.ColumnCount())
+			// Get rid of the trailing comma.
+			placeholders = placeholders[:len(placeholders)-1]
+			sqlStmt := fmt.Sprintf("INSERT INTO %s (%s) VALUES (%s)",
+				table, strings.Join(row.ColumnNames, ","), placeholders)
 			//log.Info().Str("sql", sqlStmt).Array("values", log.NewMarshaller(row.Values)).Msg("execute sql")
 			_, err := tx.Exec(sqlStmt, row.Values...)
 			if err != nil {