fix: rewrite shouldn't be performed on a column name same as the tabl…

…e name (#33)

* Rewrite shouldn't be performed on a column name same as the table name

* fix comment

* Add unit test

sources/sql/src/lib.rs

@@ -304,6 +304,12 @@ fn rewrite_column_name_in_expr(
     // Calculate the absolute index of the occurrence in string as the index above is relative to start_pos
     let idx = start_pos + idx;
 
+    // Table name same as column name
+    // Shouldn't rewrite in this case
+    if idx == 0 && start_pos == 0 {
+        return None;
+    }
+
     if idx > 0 {
         // Check if the previous character is alphabetic, numeric, underscore or period, in which case we
         // should not rewrite as it is a part of another name.
@@ -1072,6 +1078,23 @@ mod tests {
         Ok(())
     }
 
+    #[tokio::test]
+    async fn test_rewrite_same_column_table_name() -> Result<()> {
+        init_tracing();
+        let ctx = get_test_df_context();
+
+        let tests = vec![(
+            "SELECT app_table FROM (SELECT a app_table from app_table limit 100);",
+            r#"SELECT app_table FROM (SELECT remote_table.a AS app_table FROM remote_table LIMIT 100)"#,
+        )];
+
+        for test in tests {
+            test_sql(&ctx, test.0, test.1).await?;
+        }
+
+        Ok(())
+    }
+
     async fn test_sql(
         ctx: &SessionContext,
         sql_query: &str,