关于TDBGRID显示问题求助
表1:TB_USERINFO,结构:
ID USERID USERNAME
表2:TD_TEMPTOTAL,结构:
USERID TOTALDATA
表3:TD_TEMPHOUR,结构:
USERID HOURDATA
其中3表有可能统计的结果是个空表
我用:
select a.USERID,a.USERNAME,b.TOTALDATA,c.HOURDATA from TB_USERINFO a
left join (select USERID,TOTALDATA from TD_TEMPTOTAL) b on a.USERID=b.USERID
left join (select USERID,HOURDATA from TD_TEMPHOUR) c on a.USERID=c.USERID
结果HOURDATA这个地方都是空的,但是我想实现空的都显示为0,请问怎么样才能实现?