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
          Function CAST (children 1)
           ExpressionList (children 2)
            Literal \'[\\\'a\\\', \\\'b\\\']\'
            Literal \'Array(LowCardinality(String))\'
        Function tuple (children 1)
         ExpressionList (children 2)
          Literal NULL
          Function CAST (children 1)
           ExpressionList (children 2)
            Literal \'[\\\'c\\\']\'
            Literal \'Array(LowCardinality(String))\'
    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
          Function CAST (children 1)
           ExpressionList (children 2)
            Literal Array_[\'c\', NULL]
            Literal \'Array(LowCardinality(Nullable(String)))\'
        Function tuple (children 1)
         ExpressionList (children 2)
          Literal UInt64_1
          Function CAST (children 1)
           ExpressionList (children 2)
            Literal \'[\\\'a\\\', \\\'b\\\']\'
            Literal \'Array(LowCardinality(String))\'
   ExpressionList (children 1)
    Function arraySort (children 1)
     ExpressionList (children 1)
      Function arraySymmetricDifference (children 1)
       ExpressionList (children 2)
        Identifier f
        Identifier s