SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function emptyArrayToSingle (alias arr) (children 1)
     ExpressionList (children 1)
      Function arrayMap (children 1)
       ExpressionList (children 2)
        Function lambda (children 1)
         ExpressionList (children 2)
          Function tuple (children 1)
           ExpressionList (children 1)
            Identifier x
          Function toString (children 1)
           ExpressionList (children 1)
            Identifier x
        Function arrayMap (children 1)
         ExpressionList (children 2)
          Function lambda (children 1)
           ExpressionList (children 2)
            Function tuple (children 1)
             ExpressionList (children 1)
              Identifier x
            Function nullIf (children 1)
             ExpressionList (children 2)
              Identifier x
              Literal UInt64_2
          Function arrayJoin (children 1)
           ExpressionList (children 1)
            Function array (children 1)
             ExpressionList (children 3)
              Function emptyArrayUInt8 (children 1)
               ExpressionList
              Literal Array_[UInt64_1]
              Literal Array_[UInt64_2, UInt64_3]
