SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 2)
    Function materialize (alias f) (children 1)
     ExpressionList (children 1)
      Function array (children 1)
       ExpressionList (children 2)
        Function tuple (children 1)
         ExpressionList (children 2)
          Literal UInt64_1
          Literal Array_[\'a\', \'b\']
        Function tuple (children 1)
         ExpressionList (children 2)
          Literal NULL
          Literal Array_[\'c\']
    Function materialize (alias s) (children 1)
     ExpressionList (children 1)
      Function array (children 1)
       ExpressionList (children 2)
        Function tuple (children 1)
         ExpressionList (children 2)
          Literal UInt64_2
          Literal Array_[\'c\', NULL]
        Function tuple (children 1)
         ExpressionList (children 2)
          Literal UInt64_1
          Literal Array_[\'a\', \'b\']
   ExpressionList (children 1)
    Function arraySort (children 1)
     ExpressionList (children 1)
      Function arraySymmetricDifference (children 1)
       ExpressionList (children 2)
        Identifier f
        Identifier s
