SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function mapFromArrays (children 1)
     ExpressionList (children 2)
      Function array (children 1)
       ExpressionList (children 2)
        Function toNullable (children 1)
         ExpressionList (children 1)
          Function toLowCardinality (children 1)
           ExpressionList (children 1)
            Literal \'c\'
        Function toFixedString (children 1)
         ExpressionList (children 2)
          Function toFixedString (children 1)
           ExpressionList (children 2)
            Literal \'d\'
            Function toUInt256 (children 1)
             ExpressionList (children 1)
              Literal UInt64_1
          Function toLowCardinality (children 1)
           ExpressionList (children 1)
            Literal UInt64_1
      Function map (children 1)
       ExpressionList (children 4)
        Literal \'b\'
        Literal UInt64_1
        Function toFixedString (children 1)
         ExpressionList (children 2)
          Literal \'a\'
          Literal UInt64_1
        Literal UInt64_2
   ExpressionList (children 1)
    Literal UInt64_1
