SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function if (alias res) (children 1)
     ExpressionList (children 3)
      Identifier constant_null
      Identifier constant_null
      Identifier else_non_constant_nullable
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier nullable_00431