很南的sql语句
有两张表 workflow(工单表）workflowhistory(工单流转历史表） id号唯一 ，每条工单的flownumber 从1开始递增。
table workflow
id name
00 content
01 content
03 content
table workflowhistory
id flownumber dealtime
00 1 2007-10-9 20:00:00
00 2 2007-10-10 20:00:00
01 1 2007-10-9 20:00:00
01 2 2007-10-10 20:00:00
03 1 2007-9-9 12:00:00
求sql语句 把workflow workflowhistory 通过id连接起来，并且每个id只保留时间最晚的记录（或者说是flownuber最大的那条记录）id flownumber dealtime
00 2 2007-10-10 20:00:00
01 2 2007-10-10 20:00:00
03 1 2007-9-9 12:00:00
[解决办法]
select * from workflowhistory where flownumber in(select Max(flownumber) from workflowhistory group by id) and id in(select id from workflow)
这么写 可以得到你想要的结果
00 2 2007-10-10 20:00:00
01 2 2007-10-10 20:00:00
03 1 2007-9-9 12:00:00
[解决办法]
select A.id,max(flownumber) as flownumber ,max(dealtime) as dealtime,max(content) as content from workflowhistory A left join workflow B on A.id = B.id group by A.id--（所影响的行数为 3 行）00 2 2007-10-10 20:00:00.000 content 01 2 2007-10-10 20:00:00.000 content 03 1 2007-09-09 20:00:00.000 content
