SQL技巧:快速掌握一些异常精妙的\"SQL\"语句

  • 来源: 赛迪网 作者: lili   2009-08-02/09:08
  • 精妙的"SQL"语句:

    ◆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

    ◆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;

    ◆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

    ◆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

    ◆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: < 1000 p style="text-indent:2em">

    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。


    评论 {{userinfo.comments}}

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    B {{question.B}}
    C {{question.C}}
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    提交

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