SelectWithUnionQuery (children 1) ExpressionList (children 1) SelectQuery (children 3) ExpressionList (children 1) Function equals (children 1) ExpressionList (children 2) Function concat (children 1) ExpressionList (children 3) Function materialize (children 1) ExpressionList (children 1) Function toFixedString (children 1) ExpressionList (children 2) Literal \'a\' Literal UInt64_1 Literal \'b\' Literal \'c\' Literal \'abc\' TablesInSelectQuery (children 1) TablesInSelectQueryElement (children 1) TableExpression (children 1) TableIdentifier system.numbers Literal UInt64_5