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: 两张关联表,找出主表中不含有子表的记录

SQL:

select A_id from A where A_id not in (select distinct(B_id) from B)

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') &brvbar;&brvbar; '/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)

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