mysql - mysql错误代码1248

我收到错误代码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

最佳答案

错误1248是ER_DERIVED_MUST_HAVE_ALIAS，“每个派生表都必须具有自己的别名”。

连接右侧的派生表没有别名：

    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

关于mysql - mysql错误代码1248，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/17718444/