精妙sql語句
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：複製表
(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)
實現隨機取記錄:
sql server：
select top 20 * from 表 order by newid()
access：
select top 20 * from 表 order by rnd(id)
rnd(id) 其中的id是自動編號字段，可以利用其他任何數值來完成
比如用姓名字段(username)
select top 20 * from 表 order by rnd(len(username))
mysql：
select * from 表 order by rand() limit 20
精妙Sql語句
1 判斷a 表中有而 b表中沒有的記錄 select a.from tbl1 a left join tbl2 b on a.key b.key where b.key is null 雖然使用 in也可以實現，但是這種方法的效率更高一些 2 新建乙個與某個表相同結構的表 select into b...
精妙SQL語句
1 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 2.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 3 select a.title,...
精妙SQL語句
10 sql server中直接迴圈寫入資料 declare i int set i 1 while i 30 begin insert into test userid values i set i i 1 end小記儲存過程中經常用到的本週，本月，本年函式 dateadd wk,datediff...