关于For XML Path的用法
创建的表数据如图:
先看下for xml path的初始用法:select ClassID,Sex,Age,Name from #PersonInfo for xml path('PersonInfo')
从名字就看可以看出用法,for xml !!!
在使用过程中感觉通常是恶group by 一起用的。举例如下:
--统计每个班中超过22岁的男同学信息 select ClassID,COUNT(1) as '超过22岁个数',(select Name+',' from #PersonInfo where ClassID=p.ClassID for xml path ('')) as '姓名集合' from #PersonInfo p where Sex='男' and Age>22 group by ClassID order by ClassID select ClassID,(select Name+',' from #PersonInfo where ClassID=p.ClassID and Age=p.Age for xml path ('')) as '姓名集合' from #PersonInfo p where Sex='男' and Age>22 group by ClassID,Age order by ClassID select ClassID,(select Name+',' from #PersonInfo where ClassID=p.ClassID and Age=p.Age for xml path ('')) as '姓名集合' from #PersonInfo p where Sex='男' group by ClassID,Age having Age>22 order by ClassID
结果如下:
感觉having的用处没有想象中那么大。只有在group by后使用,并且是聚合函数是用处才大,不然直接写在where后面即可。
原文链接:https://www.f2er.com/xml/296651.html