mysql错误代码1248

Question

我得到一个错误代码1248，不知道为什么。提前致谢。

select substr(cbt,1,8) day, 
    max((delta_GTP_InDataPktGn+delta_GTP_OutDataPktGn))/900 
from 
(
    select a.cbt, a.datetime, 
    a.GTP_InDataPktGn - b.GTP_InDataPktGn as delta_GTP_InDataPktGn, 
    a.GTP_OutDataPktGn - b.GTP_OutDataPktGn as delta_GTP_OutDataPktGn 

    from 
     ( select cbt, STR_TO_DATE(substr(cbt,1,12),'%Y%m%d%H%i') as datetime, 
      GTP_InDataPktGn, 
      GTP_OutDataPktGn 
      from sgsn_GTP 
     ) a 

     right join 
     (
      select cbt, STR_TO_DATE(substr(cbt,1,12),'%Y%m%d%H%i') as datetime, 
      GTP_InDataPktGn, 
      GTP_OutDataPktGn 
      from sgsn_GTP 
     ) 
    on a.datetime = addtime(b.datetime,"00:15:00") 
) z 

where z.cbt between 20130429000000 and 20130430980000 
group by day 

Answer 1

错误1248是ER_DERIVED_MUST_HAVE_ALIAS， “每个派生的表必须有它自己的别名”。

对您的加盟权的派生表中没有别名：

right join 
    (
     select cbt, STR_TO_DATE(substr(cbt,1,12),'%Y%m%d%H%i') as datetime, 
     GTP_InDataPktGn, 
     GTP_OutDataPktGn 
     from sgsn_GTP 
    ) 
    --^missing b