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一组精妙的SQL语句
来源：www.mstc.com.cn  作者：佚名  发布时间：2006-12-17  ★★★〖加入收藏〗〖手机版〗
摘要：说明：复制表(只复制结构,源表名：a 新表名：b) select * into b from a where 11说明：拷贝表(拷贝数据,源表名：a 目标表名：b)insert into b(a, b, c) select d,e,f fr……
  • 说明：复制表(只复制结构,源表名：a 新表名：b)
    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)
    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
    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)
    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
    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
    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：--
    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

  • 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）

    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
    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

  • 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)

  • 一个SQL语句的问题:行列转换
    select * from v_temp
    上面的视图结果如下:
    user_name role_name
    -------------------------
    系统管理员 管理员
    feng 管理员
    feng 一般用户
    test 一般用户
    想把结果变成这样:
    user_name role_name
    ---------------------------
    系统管理员 管理员
    feng 管理员,一般用户
    test 一般用户
    ===================
    create table a_test(name varchar(20),role2 varchar(20))
    insert into a_test values('李','管理员')
    insert into a_test values('张','管理员')
    insert into a_test values('张','一般用户')
    insert into a_test values('常','一般用户')

    create function join_str(@content varchar(100))
    returns varchar(2000)
    as
    begin
    declare @str varchar(2000)
    set @str=''
    select @str=@str+','+rtrim(role2) from a_test where [name]=@content
    select @str=right(@str,len(@str)-1)
    return @str
    end
    go

    --调用：
    select [name],dbo.join_str([name]) role2 from a_test group by [name]

    --select distinct name,dbo.uf_test(name) from a_test

  • 快速比较结构相同的两表
    结构相同的两表，一表有记录3万条左右，一表有记录2万条左右，我怎样快速查找两表的不同记录？
    ============================
    给你一个测试方法，从northwind中的orders表取数据。
    select * into n1 from orders
    select * into n2 from orders

    select * from n1
    select * from n2

    --添加主键，然后修改n1中若干字段的若干条
    alter table n1 add constraint pk_n1_id primary key (OrderID)
    alter table n2 add constraint pk_n2_id primary key (OrderID)

    select OrderID from (select * from n1 union select * from n2) a group by OrderID having count(*) > 1

    应该可以，而且将不同的记录的ID显示出来。
    下面的适用于双方记录一样的情况，

    select * from n1 where orderid in (select OrderID from (select * from n1 union select * from n2) a group by OrderID having count(*) > 1)
    至于双方互不存在的记录是比较好处理的
    --删除n1,n2中若干条记录
    delete from n1 where orderID in ('10728','10730')
    delete from n2 where orderID in ('11000','11001')

    --*************************************************************
    -- 双方都有该记录却不完全相同
    select * from n1 where orderid in(select OrderID from (select * from n1 union select * from n2) a group by OrderID having count(*) > 1)
    union
    --n2中存在但在n1中不存的在10728,10730
    select * from n1 where OrderID not in (select OrderID from n2)
    union
    --n1中存在但在n2中不存的在11000,11001
    select * from n2 where OrderID not in (select OrderID from n1)

    一组精妙SQL语句
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