SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Asterisk
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 2)
          ExpressionList (children 2)
           Function if (alias error_message) (children 1)
            ExpressionList (children 3)
             Function isValidUTF8 (children 1)
              ExpressionList (children 1)
               Identifier 1
             Literal NULL
             Literal \'error!\'
           Function if (alias valid) (children 1)
            ExpressionList (children 3)
             Function isNull (children 1)
              ExpressionList (children 1)
               Identifier error_message
             Literal UInt64_1
             Literal UInt64_0
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier testdata
   Identifier valid
