Code review comments

Author: yoavcloud

src/ast/query.rs

@@ -2533,7 +2533,11 @@ pub struct TableAlias {
     pub name: Ident,
     /// Optional column aliases declared in parentheses after the table alias.
     pub columns: Vec<TableAliasColumnDef>,
-    /// Optional PartiQL index alias declared with `AT`.
+    /// Optional PartiQL index alias declared with `AT`. For example:
+    /// ```sql
+    /// SELECT element, index FROM bar AS b, b.data.scalar_array AS element AT index
+    /// ```
+    /// See: <https://docs.aws.amazon.com/redshift/latest/dg/query-super.html>
     pub at: Option<Ident>,
 }
 

tests/sqlparser_redshift.rs

@@ -520,11 +520,12 @@ fn test_null_treatment_inside_and_outside_window_function() {
 
 #[test]
 fn test_partiql_from_alias_with_at_index() {
-    redshift().verified_stmt("SELECT * FROM lineitem AS l (a, b, c) AT idx");
+    let dialects = all_dialects_where(|d| d.supports_partiql());
+    dialects.verified_stmt("SELECT * FROM lineitem AS l (a, b, c) AT idx");
 
     let sql =
         "SELECT index, val FROM (SELECT array('AAA', 'BBB') AS val) AS b, b.val AS val AT index";
-    let select = redshift().verified_only_select(sql);
+    let select = dialects.verified_only_select(sql);
 
     match &select.from[1].relation {
         TableFactor::Table { name, alias, .. } => {