sql语句如何写

1、一稍僚敉视个表与一个查询结果集进行条件判断后，表的子集修改对应字段，关键词，update，inner join,select.UPDATEzl_zbx_9_0408 z2 INNER joi荏鱿胫协n (SELECT subtask.id as subid,zl.workdate, zl.newsubtaskname,subtask.task_id,zl.usernamefrom zl_zbx_9_0408 zl,sub_task subtask-- ,work_task taskWHERE zl.newsubtaskname = subtask.subtask_nameand zl.username='周'and subtask.task_id = 58) as abcon z2.newsubtaskname = abc.newsubtasknameand abc.task_id=58AND abc.workdate = z2.workdateand z2.username='周'set z2.newsubtaskid = abc.subid;

2、将一个查询结果集插入到另一个表中，关键词，insert，selectINSER哌囿亡噱T INTO working_hours(task_id,task_name,subtask忧溲枷茫_id,subtask_name,user_id,`level`,work_date,realname,workinghours,work_descr,`status`)SELECT z2.newtaskid,z2.newtaskname,z2.newsubtaskid,z2.newsubtaskname,z2.user_id,z2.`level`,z2.workdate,z2.username,z2.workhours,z2.workdesc,1from zl_zbx_9_0408 z2,sub_task subtask-- ,work_task taskWHERE z2.newsubtaskname = subtask.subtask_nameand z2.username='周'and subtask.task_id = 58;

3、查询重复的记录，例如一个表中重名的记录。关键词，select，group by，having eg1：-- 查询user_info里重名的SELECT realname,count(realname) from user_info GROUP BY realname HAVING count(realname)>=2;eg2：SELECT hw ,count(hw) cou from ( select id , CONCAT(user_id,'_',work_date,'_',subtask_id) as hw from working_hours)ww group by hw HAVING cou>1;

4、-- 更新useridUPDATE renwu_zirenwu_tihuan0510 zbx INNER JOIN user_info uiset zbx.userid = ui.idWHERE zbx.realname = ui.realnameand ui.user_type = 0

5、‍-- 删除数据量大的工时SELECT-- * SUM(workinghours)from working_hoursWHERE realname in('李')and work_date>='2013-12-01'and work_date<='2013-12-31'and (DAYOFWEEK(work_date)=1 or DAYOFWEEK(work_date)=7)ORDER BY work_date-- 查询没生成报表的任务 DESC work_task;desc work_order;select distinct wh.task_id from working_hours wh,work_task wtWHERE wh.work_date>='2013-10-01'and wh.work_date<='2013-12-31'and wh.task_id = wt.id;