UPDATE A.A3 = A.A3+B.B3 的问题
表A 结构 : A1 , A2 ,A3
表B 结构: B1, B2, B3
其中 A1 ,B1 为PK ,切值相同 就是可以使用A1 = B1 了.
请问用SQL 语句或过程该如何实现如下的功能???
更新A 表的 A3 ,用A.A3 与B.B3之和更新.
3>update A
set A3 = (select A.A3 + B.B3 from B where A.A1 = B.B1) ;
7>update (select a1,a3,b1,b3 from a,b where a1=b1) set a3=a3+b3
开执行计划, 谈论效率是没有太多的意义的^_^..
三楼的写法与7楼的写法得到的结果是不同的.
三楼的写法会更新所有记录, 而7楼的写法只修改两者相交的相关记录信息.
7楼的写法可以更加轻易的控制这条update语句的执行计划, 不过要求B表必须在对应的字段上有主键索引:) , 在B表在对应字段上有主键索引的时候, 建议使用7楼的写法.
可以参考一下这个帖子^_^
http://www.cnoug.org/viewthread.php?tid=44070
(测试没有成功..不知道怎么搞的.)
参考了下面的:
非常佩服。抱着学习的态度，重写了一下三楼的，在没有主键的情况，请指教：
update a
set a3=(select a3+b3 from b where a1=b1)
where a1=(select b1 from b where a1=b1)
如下:
update con_eme_on20050309 a set a.con_price=(select a.con_price+(b.annuity-a.annuity)+(b.nojob-a.nojob)+(b.medicare-a.medicare)+(b.birthfee-a.birthfee)+(b.bruisefee-a.bruisefee) from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base),a.emp_base=(select b.emp_base from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base),a.annuity=(select b.annuity from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base),a.nojob=(select b.nojob from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base),a.medicare=(select b.medicare from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base),a.birthfee=(select b.birthfee from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base),a.bruisefee=(select b.bruisefee from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base),a.nojobbase=(select b.nojobbase from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base),a.mediabase=(select b.mediabase from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base),a.birthbase=(select b.birthbase from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base),a.bruisebase=(select b.bruisebase from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base)
where a.emp_cod in(select b.emp_cod from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base)
公积金:
update con_eme_on20050309 a set a.con_price=(select a.con_price+(b.accumulation-a.accumulation) from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base),a.accumulation=(select b.accumulation from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base),a.accumulationbase=(select b.accumulationbase from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base),a.accumulationbase1=(select b.accumulationbase1 from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base)
where a.emp_cod in(select b.emp_cod from con_eme_on200404 b where a.emp_cod=b.emp_cod and a.if_act='1' and a.emp_base!=b.emp_base)
