精妙SQL语句大全

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 a;
   
    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)