DescribeQuery (children 1) TableExpression (children 1) Subquery (children 1) SelectWithUnionQuery (children 1) ExpressionList (children 1) SelectQuery (children 2) ExpressionList (children 3) Literal UInt64_1 (alias id) Literal UInt64_2 (alias value) Asterisk TablesInSelectQuery (children 1) TablesInSelectQueryElement (children 1) TableExpression (children 1) TableIdentifier test_table (alias t1)