DB2 实现环比的sql

 DB2的sql语句：

select a.op_date , plan_user_num,pre_plan_user_num ,ROUND(COALESCE(CAST(a.plan_user_num AS DOUBLE), 0)/a.pre_plan_user_num, 2)  huanbi 

from (select op_date,plan_user_num,(select plan_user_num from mtl_camp_evaluate_dm w where date(w.op_date) = date(t.op_date) - 1 day ) pre_plan_user_num  from mtl_camp_evaluate_dm t order by t.op_date) a

 

查询结果：

   op_date  plan_user_num pre_plan_user_num huanbi

2010-07-21	188	[Null]	[Null]
2010-07-22	180	188	0.96
2010-07-23	200	180	1.11
2010-07-24	180	200	0.9
2010-07-25	160	180	0.89