Explain EXPLAIN SYNTAX (children 1) SelectWithUnionQuery (children 1) ExpressionList (children 1) SelectQuery (children 2) ExpressionList (children 1) Asterisk (children 1) ColumnsTransformerList (children 2) ColumnsExceptTransformer (children 1) Identifier i ColumnsApplyTransformer TablesInSelectQuery (children 1) TablesInSelectQueryElement (children 1) TableExpression (children 1) TableIdentifier columns_transformers