如题所述
表å段åæ°æ®å¤ªå¤ï¼æè¿è¾¹èªå·±å»ºè¡¨å°±ç¨äºå 个è½ç¨å¾ä¸çå段
tstudent表ï¼
tcourse表ï¼
tgrade表ï¼
åsqlè¯å¥ï¼
select t1.ç级,str(round(sum(switch(t2.课ç¨å='é«çæ°å¦',t2.åæ ¼äººæ°,true,0))/t1.人æ°,4)*100)+'%' as é«çæ°å¦,str(round(sum(switch(t2.课ç¨å='计ç®æºåç',t2.åæ ¼äººæ°,true,0))/t1.人æ°,4)*100)+'%' as 计ç®æºåç,
str(round(sum(switch(t2.课ç¨å='ä¸ä¸è±è¯',t2.åæ ¼äººæ°,true,0))/t1.人æ°,4)*100)+'%' as ä¸ä¸è±è¯
from
(select ç级,count(*) as äººæ° from tstudent group by ç级) as t1,
(select a.ç级,b.课ç¨å,count(*) as åæ ¼äººæ° from tstudent as a,tcourse as b,tgrade as c where a.å¦å·=c.å¦å· and b.课ç¨ç¼å·=c.课ç¨ç¼å· group by a.ç级,b.课ç¨å) as t2
where t1.ç级=t2.ç级
group by t1.ç级,t1.人æ°
æ¥è¯¢ç»æï¼
说æï¼sqlè¯å¥ä½ åºè¯¥ç´æ¥å¯ä»¥å¨sqlçªå£è¿è¡ï¼å 为å段åä»ä¹çï¼ææ¯æç §ä½ æä¾ç表æ¥åçãä¿åæJCqT6çè¯ï¼ä½ ç´æ¥å¨sqlçªå£ä¸å ³éçæ¶åææ示ï¼ç¶åä½ è¾å ¥ååå°±å¯ä»¥ï¼å°±æ¯è¿ä¸ªçé¢ã
温馨提示:答案为网友推荐,仅供参考
第1个回答 2018-10-24
文件能发出来就可以帮你写!!!追问
兄弟 邮箱