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精妙SQL语句介绍

说明:复制表(只复制结构,源表名:a 新表名:b)  

  sql: select * into b from a where 1<>1

  说明:拷贝表(拷贝数据,源表名:a 目标表名:b)  

  sql: insert into b(a, b, c) select d,e,f from b;

  说明:显示文章、提交人和最后回复时间  

  sql: select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b

  说明:外连接查询(表名1:a 表名2:b)  

  sql: select a.a, a.b, a.c, b.c, b.d, b.f from a left out join b on a.a = b.c

  说明:日程安排提前五分钟提醒  

  sql: select * from 日程安排 where datediff(''minute'',f开始时间,getdate())>5  

  说明:两张关联表,删除主表中已经在副表中没有的信息

  sql:   

  delete from info where not exists ( select * from infobz where info.infid=infobz.infid

  说明:--

  sql:   

  select a.num, a.name, b.upd_date, b.prev_upd_date

   from table1,

   (select x.num, x.upd_date, y.upd_date prev_upd_date

   from (select num, upd_date, inbound_qty, stock_onhand

   from table2

   where to_char(upd_date,''yyyy/mm'') = to_char(sysdate, ''yyyy/mm'')) x,

   (select num, upd_date, stock_onhand

   from table2

   where to_char(upd_date,''yyyy/mm'') =

   to_char(to_date(to_char(sysdate, ''yyyy/mm'') ¦¦ ''/01'',''yyyy/mm/dd'') - 1, ''yyyy/mm'') y,

   where x.num = y.num (+)

   and x.inbound_qty + nvl(y.stock_onhand,0) <> x.stock_onhand b

  where a.num = b.num

  说明:--

  sql:   

  select * from studentinfo where not exists(select * from student where studentinfo.id=student.id) and 系名称=''"&strdepartmentname&"'' and 专业名称=''"&strprofessionname&"'' order by 性别,生源地,高考总成绩

  说明:

  从数据库中去一年的各单位电话费统计(电话费定额贺电化肥清单两个表来源)

  sql:  

  select a.userper, a.tel, a.standfee, to_char(a.telfeedate, ''yyyy'') as telyear,

   sum(decode(to_char(a.telfeedate, ''mm''), ''01'', a.factration)) as jan,

   sum(decode(to_char(a.telfeedate, ''mm''), ''02'', a.factration)) as fri,

   sum(decode(to_char(a.telfeedate, ''mm''), ''03'', a.factration)) as mar,

   sum(decode(to_char(a.telfeedate, ''mm''), ''04'', a.factration)) as apr,

   sum(decode(to_char(a.telfeedate, ''mm''), ''05'', a.factration)) as may,

   sum(decode(to_char(a.telfeedate, ''mm''), ''06'', a.factration)) as jue,

   sum(decode(to_char(a.telfeedate, ''mm''), ''07'', a.factration)) as jul,

   sum(decode(to_char(a.telfeedate, ''mm''), ''08'', a.factration)) as agu,

   sum(decode(to_char(a.telfeedate, ''mm''), ''09'', a.factration)) as sep,

   sum(decode(to_char(a.telfeedate, ''mm''), ''10'', a.factration)) as oct,

   sum(decode(to_char(a.telfeedate, ''mm''), ''11'', a.factration)) as nov,

   sum(decode(to_char(a.telfeedate, ''mm''), ''12'', a.factration)) as dec

  from (select a.userper, a.tel, a.standfee, b.telfeedate, b.factration

   from telfeestand a, telfee b

   where a.tel = b.telfax) a

  group by a.userper, a.tel, a.standfee, to_char(a.telfeedate, ''yyyy'')

  说明:四表联查问题:  

  sql: select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where .....

  说明:得到表中最小的未使用的id号

  sql: 

  select (case when exists(select * from handle b where b.handleid = 1) then min(handleid) + 1 else 1 end) as handleid

   from handle

   where not handleid in (select a.handleid - 1 from handle a) 
昵称: isno  时间: 2008-07-24 09:29:00