SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Identifier id
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier t1
   Function equals (children 1)
    ExpressionList (children 2)
     Function tuple (children 1)
      ExpressionList (children 2)
       Identifier s1
       Identifier s2
     Function CAST (children 1)
      ExpressionList (children 2)
       Subquery (children 1)
        SelectWithUnionQuery (children 1)
         ExpressionList (children 1)
          SelectQuery (children 3)
           ExpressionList (children 2)
            Identifier s1
            Identifier s2
           TablesInSelectQuery (children 1)
            TablesInSelectQueryElement (children 1)
             TableExpression (children 1)
              TableIdentifier t1
           Function equals (children 1)
            ExpressionList (children 2)
             Identifier s1
             Literal \'a\'
       Literal \'text\'
