SelectWithUnionQuery (children 1) ExpressionList (children 1) SelectQuery (children 2) ExpressionList (children 1) Asterisk TablesInSelectQuery (children 2) TablesInSelectQueryElement (children 1) TableExpression (children 1) TableIdentifier empty_table TablesInSelectQueryElement (children 2) TableExpression (children 1) TableIdentifier t1 TableJoin (children 1) Function equals (children 1) ExpressionList (children 2) Literal UInt64_1 Literal UInt64_1