select *
from bbs_forums
where (left(ltrim(name), 3) = '嘉年華')
【重點】like我就不多說了,先看left函式:
left(要查詢的列名,左起的前幾個字元)='前幾個字元為(二聲)什麼'
再看ltrim函式,這個簡單了,去除某欄位的左邊的空格
1. 說明：複製表(只複製結構，源表名：a，新表名：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;
sql: select a.title, a.username, b.adddate
from table a,(
select max(adddate) adddate
from table where table.title=a.title) b
4. 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
6. 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 );
7. 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;
8. 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&"''