如何从【rú hé cóng】一位菜【yī wèi cài】🏌鸟蜕变【niǎo tuì biàn】成为高🈷手，灵活使【líng huó shǐ】🎾用的SQL语句是【yǔ jù shì】必不可🎍少的。本文收集了部【jí le bù】分比较🥥经典【jīng diǎn】，常用的SQL语句供大家参【dà jiā cān】考，希望对【xī wàng duì】大家有🌌所帮助。

　　说明【shuō míng】：复制表(只复制结构💦,源表名【biǎo míng】🎑：a 新表名【biǎo míng】🔡：b)　　

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

　　说明【shuō míng】：拷贝表🔇(拷贝数【kǎo bèi shù】据【jù】⏭,源表名【biǎo míng】🎑：a 目标表【mù biāo biǎo】名🔡：b)　　

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

　　说明【shuō míng】：显示文【xiǎn shì wén】章【zhāng】、提交人🏜和最后📨回复时🐩间【jiān】　　

　　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【shuō míng】：外连接🗳查询🌄(表名【biǎo míng】🔡1：a 表名【biǎo míng】🔡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【shuō míng】：日程安【rì chéng ān】🚲排提前【pái tí qián】五分钟提醒　　

　　SQL: select * from 日程安【rì chéng ān】🚲排 where datediff('minute',f开始时间【jiān】,getdate())>5　　

　　说明【shuō míng】：两张关联表🔶，删除主【shān chú zhǔ】表中已【biǎo zhōng yǐ】经在副【jīng zài fù】表中没有的信息🔇

　　SQL: 　　

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

　　说明【shuō míng】：--

　　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【shuō míng】：--

　　SQL: 　　

　　select * from studentinfo where not exists(select * from student where studentinfo.id=student.id) and 系名【xì míng】🔡称【chēng】='"&strdepartmentname&"' and 专业名【zhuān yè míng】🔡称【chēng】='"&strprofessionname&"' order by 性别,生源地,高考总成绩🥋

　　说明【shuō míng】：

　　从数据【jù】📮库中去【kù zhōng qù】一年的【yī nián de】各单位【gè dān wèi】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【shuō míng】：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【shuō míng】：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)