精妙SQL語句介紹

2021-04-06 12:20:37 字數 3248 閱讀 8188

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

說明:

從資料庫中去一年的各單位**費統計(**費定額賀電化肥清單兩個表**)

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...