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          高手是怎樣煉成的:精妙SQL語(yǔ)句介紹

          我要評(píng)論 2009/04/15 15:56:05 來(lái)源:綠色資源網(wǎng) 編輯:編輯整理 [ ] 評(píng)論:0 點(diǎn)擊:588次

            如何從一位菜鳥(niǎo)蛻變成為高手,靈活使用的SQL語(yǔ)句是必不可少的。本文收集了部分比較經(jīng)典,常用的SQL語(yǔ)句供大家參考,希望對(duì)大家有所幫助。

            說(shuō)明:復(fù)制表(只復(fù)制結(jié)構(gòu),源表名:a 新表名:b)  

            SQL: select * into b from a where 1<>1

            說(shuō)明:拷貝表(拷貝數(shù)據(jù),源表名:a 目標(biāo)表名:b)  

            SQL: insert into b(a, b, c) select d,e,f from b;

            說(shuō)明:顯示文章、提交人和最后回復(fù)時(shí)間  

            SQL: select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b

            說(shuō)明:外連接查詢(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

            說(shuō)明:日程安排提前五分鐘提醒  

            SQL: select * from 日程安排 where datediff('minute',f開(kāi)始時(shí)間,getdate())>5  

            說(shuō)明:兩張關(guān)聯(lián)表,刪除主表中已經(jīng)在副表中沒(méi)有的信息

            SQL:   

            delete from info where not exists ( select * from infobz where info.infid=infobz.infid

            說(shuō)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

            說(shuō)明:--

            SQL:   

            select * from studentinfo where not exists(select * from student where studentinfo.id=student.id) and 系名稱='"&strdepartmentname&"' and 專業(yè)名稱='"&strprofessionname&"' order by 性別,生源地,高考總成績(jī)

            說(shuō)明:

            從數(shù)據(jù)庫(kù)中去一年的各單位電話費(fèi)統(tǒng)計(jì)(電話費(fèi)定額賀電化肥清單兩個(gè)表來(lái)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')

            說(shuō)明:四表聯(lián)查問(wèn)題:  

            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 .....

            說(shuō)明:得到表中最小的未使用的ID號(hào)

            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)

          關(guān)鍵詞:SQL語(yǔ)句

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