精妙SQL語句介紹

2021-04-02 02:38:43 字數 2945 閱讀 6390

說明:複製表(只複製結構,源表名:a 新錶名:b)

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

說明:拷貝表(拷貝資料,源表名:a 目標表名:b)

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

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:外連線查詢(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   

sql: select * from 日程安排 where datediff('minute',f開始時間,getdate())>5   

說明: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 系名稱='"&strdepartmentname&"' and 專業名稱='"&strprofessionname&"' order by 性別,生源地,高考總成績   

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')   

說明:四表聯查問題:

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 .....   

說明:得到表中最小的未使用的id號

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) 

精妙sql語句介紹

說明 複製表 只複製結構,源表名 a 新錶名 b sql select into b from a where 1 1 說明 拷貝表 拷貝資料,源表名 a 目標表名 b sql insert into b a,b,c select d,e,f from b sql select a.title,a....

精妙SQL語句介紹

說明 複製表 只複製結構,源表名 a 新錶名 b sql select into b from a where 1 1 說明 拷貝表 拷貝資料,源表名 a 目標表名 b sql insert into b a,b,c select d,e,f from b sql select a.title,a....

精妙SQL語句介紹

sql select intobfromawhere1 1 說明 拷貝表 拷貝資料,源表名 a目標表名 b sql insertintob a,b,c selectd,e,ffromb sql selecta.title,a.username,b.adddatefromtablea,selectma...