mysql实现分组后排序的功能

看了网友的sql分析，自己写一个：

oracle：分组后排序
SELECT  NAME,score, DENSE_RANK() OVER(ORDER BY score DESC) AS dense_r FROM students;

mysql：分组后排序
SELECT NAME,@rk:=IF(@score=score,@rk,@rk+1) dense_r,@score:=score score FROM (SELECT NAME,score FROM students ORDER BY score DESC)a, (SELECT @rk:=0,@score:=NULL)b;

写了一个我自己的sql语句：

-- 1：这个是关联查询出合同和租金规则的
select hlcRentRuleStartDate, hlcRentRuleEndDate, @rk:=IF(@HlcBarCode=HlcBarCode,@rk,@rk+1),@HlcBarCode:=HlcBarCode HlcBarCode
 from (
      select t1.hlcRentRuleStartDate, t1.hlcRentRuleEndDate, t1.HlcRentRulePeriod, t2.HlcBarCode, t2.HlcCode from tHLCRentRlue t1 left join tHouseLeaseContract t2
            on t1.hlcRentRuleContractCode=t2.HlcCode where t2.insertTime >= '2022-01-01' and t2.insertTime <= '2023-02-01' and t1.HlcRentRulePeriod='PayCyc_006'                                                                                                                                                                  and t1.HlcRentRulePeriod='PayCyc_006'
          ) a, (SELECT @rk:=0,@HlcBarCode:=NULL)b;

希望此文帮助到你！