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