mysql排名

转载自思心思危http://www.cnblogs.com/zengguowang/p/5541431.html

 

一、sql1｛不管数据相同与否，排名依次排序（1,2,3,4,5,6,7.....）｝

SELECTobj.user_id,
　　 obj.score,
　　@rownum := @rownum + 1 AS rownum
FROM(SELECTuser_id,scoreFROM`sql_rank`ORDER BYscore DESC) AS obj,(SELECT @rownum := 0) r

二、sql2｛只要数据有相同的排名就一样，排名依次排序（1,2,2,3,3,4,5.....）｝

SELECTobj.user_id,obj.score,
CASE
WHEN @rowtotal = obj.score THEN  @rownum
WHEN @rowtotal := obj.score THEN @rownum :=@rownum + 1
WHEN @rowtotal = 0 THEN  @rownum :=@rownum + 1
END AS rownum
FROM(SELECTuser_id,scoreFROM`sql_rank`ORDER BYscore DESC) AS obj,(SELECT @rownum := 0 ,@rowtotal := NULL) r

三、sql2｛只要数据有相同的排名就一样，但是相同排名也占位，排名依次排序（1,2,2,4,5,5,7.....）｝　　

　　　此时需呀再增加一个变量，来记录排序的号码（自增）

SELECTobj_new.user_id,obj_new.score,obj_new.rownum
FROM(SELECTobj.user_id,obj.score,@rownum := @rownum + 1 AS num_tmp,@incrnum := CASEWHEN @rowtotal = obj.score THEN@incrnumWHEN @rowtotal := obj.score THEN@rownumEND AS rownumFROM(SELECTuser_id,scoreFROM`sql_rank`ORDER BYscore DESC) AS obj,(SELECT@rownum := 0 ,@rowtotal := NULL ,@incrnum := 0) r) AS obj_new