条件一 typeID=1
查询表 titleInfo
select titleID,titleTitle,userID,titleTime from titleInfo where typeID=1
根据上表查询的结果 titleID 做为条件二
查询表reTitle
select rePart from reTitle Where titleID想要的做的是论坛显示回复贴数,根据所选板块进行显示主题 在主题后面显示回复数.使用联合查询:
select a.titleID,a.titleTitle,a.userID,a.titleTime,count(b.titleID) as reTitleNum from titleInfo a,reTitle b where a.titleId=b.titleid group by a.titleID,a.titleTitle,a.userID,a.titleTime order by a.titleTime desc问题是联合查询后只显示出了 有回复的主题 其他无回复的主题并未显示出来.求教这各问题应该怎样去处理
查询表 titleInfo
select titleID,titleTitle,userID,titleTime from titleInfo where typeID=1
根据上表查询的结果 titleID 做为条件二
查询表reTitle
select rePart from reTitle Where titleID想要的做的是论坛显示回复贴数,根据所选板块进行显示主题 在主题后面显示回复数.使用联合查询:
select a.titleID,a.titleTitle,a.userID,a.titleTime,count(b.titleID) as reTitleNum from titleInfo a,reTitle b where a.titleId=b.titleid group by a.titleID,a.titleTitle,a.userID,a.titleTime order by a.titleTime desc问题是联合查询后只显示出了 有回复的主题 其他无回复的主题并未显示出来.求教这各问题应该怎样去处理
(select count(reTitle.titleID) from reTitle Where reTitle.titleID=titleInfo.titleID) as reTitleNum
from titleInfo where typeID=1
select a.titleID
,a.titleTitle
,a.userID
,a.titleTime
,(select count(b.titleID) from reTitle b where a.titleID = b.titleID )as reTitleNum
from titleInfo aselect a.titleID,a.titleTitle,a.userID,a.titleTime,count(b.titleID) as reTitleNum
from titleInfo a
left join reTitle b on a.titleId=b.titleid
group by a.titleID,a.titleTitle,a.userID,a.titleTime
order by a.titleTime desc
from titleInfo left join reTitle on titleInfo.titleID = reTitle.titleID
where typeID=1
group by a.titleID,a.titleTitle,a.userID,a.titleTime order by a.titleTime desc