SelectWithUnionQuery (children 1) ExpressionList (children 1) SelectQuery (children 3) ExpressionList (children 2) Literal UInt64_6 Asterisk TablesInSelectQuery (children 1) TablesInSelectQueryElement (children 1) TableExpression (children 1) TableIdentifier merge_tree ExpressionList (children 1) OrderByElement (children 1) Identifier d