請(qǐng)教一個(gè)關(guān)于informix語(yǔ)句的問(wèn)題

field

情況是這樣的,有一個(gè)表有以下字段:
zh,fse,rq
其中有很多記錄zh字段是相同的,我只想取出其中rq最大的那條記錄的fse,請(qǐng)教這個(gè)語(yǔ)句如何寫?

wenlq

try
select unique zh from tab into temp tmpzh;
select a.* from tab a,tmpzh b   
where  a.zh = b.zh and rq = ( select max( rq ) from tab where zh = b.zh ) ;

shanshl

select tb1.fse
from tbname tb1
where tb1.rq=(select max(tb2.rq) from tbname tb2 where tb1.zh=tb2.zh)
這樣應(yīng)該可以吧

john_student

1. 
   
2. select zh, max(rq) as maxrq
   
3. from tab
   
4. group by zh
   
5. into temp tab_tmp ;
   
6. select a.zh, a.rq, a.fse
   
7. from tab a, tab_tmp b
   
8. where a.zh = b.zh
   
9. and a.rq = b.maxrq ;
   

復(fù)制代碼