[導讀] 精妙的"SQL"語句: ◆複製表(只複製結構,來源表名:a 新表名:b) SQL: select * into b from a where 1<>1 ◆拷貝表(拷貝資料,來源表名:a 目標表名:b) SQL: insert into b(a, b, c) se
精妙的"SQL"語句:
◆複製表(只複製結構,來源表名:a 新表名:b)
SQL: select * into b from a where 1<>1
◆拷貝表(拷貝資料,來源表名:a 目標表名:b)
SQL: insert into b(a, b, c) select d,e,f from b;
◆顯示文章、提交人與最後回覆時間
SQL: select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b
◆說明:外連結查詢(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
◆日程安排提前五分鐘提醒
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5
◆兩張關聯表,刪除主表中已經在副表中沒有的資訊
SQL: delete from info where not exists ( select * from infobz where info.infid=infobz.infid )
◆說明:
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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