精妙SQL语句精华 Subtle SQL statements essence

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)