快速掌握一些异常精妙的SQL语句

[导读] 　　精妙的"SQL"语句: ◆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　　 ◆拷贝表(拷贝数据,源表名：a 目标表名：b) SQL: insert into b(a, b, c) se

　　精妙的"SQL"语句:

◆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

◆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;

◆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

◆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 　　

◆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

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