InsertQuery   (children 2)
 Identifier test_serialization
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 1)
    ExpressionList (children 2)
     Literal UInt64_2
     Function groupConcatState (children 1)
      ExpressionList (children 1)
       Literal \'Second\'
