sql·Ö×é²éѯÎÊÌâ
Çé¾°Ò»£º
±íÖÐÊý¾Ý
name score
aaa 11
aaa 19
bbb 12
bbb 18
ccc 19
ddd 21
ÆÚÍû²éѯ½á¹ûÈçÏÂ
name score
aaa 30
bbb 30
ccc 19
ddd 21
Sql´úÂë
---¼ì²é±íÊÇ·ñ´æÔÚ
if exists(select * from sysobjects where name='testSum')
drop table testSum
go
---´´½¨±í
create table testSum
(
tid int primary key identity(1,1),
tname varchar(30) null,
tscor int null
)
go
insert into testSum (tname,tscor)
select 'aaa',11
union all
select 'aaa',19
union all
select 'bbb',12
union all
select 'bbb',18
union all
select 'ccc',19
union all
select 'ddd',21
---²éѯÓï¾ä
select tname ,sum(tscor) from testSum group by tname
---Ö»²éѯtscor×ܺÍΪ30µÄ
select tname ,sum(tscor) from testSum group by tname having sum(tscor)=30
---¼ì²é±íÊÇ·ñ´æÔÚ
if exists(select * from sysobjects where name='testSum')
drop table testSum
go
---´´½¨±í
create table testSum
(
tid int primary key identity(1,1),
tname varchar(30) null,
tscor int null
)
go
insert into testSum (tname,tscor)
select 'aaa',11
union all
select 'aaa',19
union
Ïà¹ØÎĵµ£º
ÒÔÇ°¶ÔÓÚSql ServerÖÐCaseÃüÁîµÄÓ÷¨Ò»Ö±²»ÊǺÜÁ˽⣬½ñÌìͨ¹ýÉÏÍø²éÁËһЩ×ÊÁÏ£¬½«Case»ù±¾µÄÓ÷¨×ܽáһϡ£
CaseÃüÁîÓÐÁ½ÖÖÓï·¨£º
A£©CASE<ÔËËãʽ>
WHEN <ÔËËãʽ> THEN <ÔËËãʽ>
……
WHEN <ÔËËãʽ> THEN <ÔËËãʽ>
[ELSE<ÔËËãʽ> ......
ת×ÔCSDNÂÛ̳£ºchaihuoniu
ÏÂÁÐÓï¾ä²¿·ÖÊÇMssqlÓï¾ä£¬²»¿ÉÒÔÔÚaccessÖÐʹÓá£
SQL·ÖÀࣺ
DDL—Êý¾Ý¶¨ÒåÓïÑÔ(CREATE£¬ALTER£¬DROP£¬DECLARE)
DML—Êý¾Ý²Ù×ÝÓïÑÔ(SELECT£¬DELETE£¬UPDATE£¬INSERT)
DCL—Êý¾Ý¿ØÖÆÓïÑÔ(GRANT£¬REVOKE£¬COMMIT£¬ROLLBACK)
Ê×ÏÈ,¼òÒª½éÉÜ»ù´¡Óï¾ä£º
1¡¢ËµÃ÷£º´´½¨Êý¾ ......
Ê×ÏÈÅäÖÃSQLSERVER2005£º
´ò¿ª”Microsoft SQL Server Management Studio“Ö±½ÓÓÃWindows Óû§Á¬½Ó½øÈ룬ÔÙÔÚ“°²È«ÐÔ”ÖеēµÇ¼Ãû”Äڵēн¨µÇ¼Ãû”£¬Äã¾Í¶ÔÓ¦µÄÌíºÃ“È·¶¨”¾Í¿ÉÒÔÁË¡£
ÔÙÔÚÄã¶ÔÓ¦µÄ“Êý¾Ý¿â”Àï“°²È«ÐÔ&r ......
Õâ¾ÍÒª´ÓË«ÒýºÅºÍµ¥ÒýºÅµÄ×÷Óý²Æð£º
Ë«ÒýºÅÀïÃæµÄ×ֶλᾹý±àÒëÆ÷½âÊÍÈ»ºóÔÙµ±×÷HTML´úÂëÊä³ö£¬µ«Êǵ¥ÒýºÅÀïÃæµÄ²»ÐèÒª½âÊÍ£¬Ö±½ÓÊä³ö¡£ÀýÈ磺
$abc='I love u';
echo $abc //½á¹ûÊÇ:I love u
echo '$abc' //½á¹ûÊ ......
SQL> select * from dept where deptno=&tt;
Enter value for tt:20
DEPTNO DNAME LOC
------ -------------- -------------
10 ACCOUNTING NEW YORK
ÕâÑùÎÞÂÛÊäÈë¶àÉÙ´ÎttµÄÖµ£¬ÏµÍ³Ö»½¨Á¢Ò»¸öÖ´Ðмƻ®£¬Ì ......