MySQL高手篇:精妙SQL语句介绍

如何从一位菜鸟蜕变成为高手，灵活使用的sql语句是必不可少的。本文收集了部分比较经典，常用的sql语句供大家参考，希望对大家有所帮助。

说明：复制表(只复制结构,源表名：a 新表名：b)

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

说明：拷贝表(拷贝数据,源表名：a 目标表名：b)

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

说明：显示文章、提交人和最后回复时间

sql:selecta.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b

说明：外连接查询(表名1：a 表名2：b)

sql:selecta.a, a.b, a.c, b.c, b.d, b.f from a left out join b on a.a = b.c

说明：日程安排提前五分钟提醒

sql:select* from 日程安排 where datediff(''minute'',f开始时间,getdate())>5

说明：两张关联表，删除主表中已经在副表中没有的信息

sql:

delete from info where not exists (select* from infobz where info.infid=infobz.infid

说明：--

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'') &brvbar;&brvbar; ''/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

说明：--

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

说明：

从数据库中去一年的各单位电话费统计(电话费定额贺电化肥清单两个表来源）

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'')

说明：四表联查问题：

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 .....

说明：得到表中最小的未使用的id号

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)

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