SQL语句先前写的时候,很容易把一些特殊的用法忘记,我特此整理了一下SQL语句操作。 2?hc94
hiWfVz{~
B:om61Dn
一、基础 `x2Q:&.H`
1、说明:创建数据库 Q%61_l
CREATE DATABASE database-name <\<[J0
2、说明:删除数据库 C~IsYdln
drop database dbname y -j3d)T
3、说明:备份sql server 4hb<EH'_&
--- 创建 备份数据的 device X(nbfh?n
USE master I;]Q}SUsm
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' S3rN]!B+
--- 开始 备份 <RfPd+</
BACKUP DATABASE pubs TO testBack }=CL/JHz
4、说明:创建新表 ?z>7&
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) E? 1"&D
m
根据已有的表创建新表: kXGJZ$
A:create table tab_new like tab_old (使用旧表创建新表) ;*K@8GnU
B:create table tab_new as select col1,col2... from tab_old definition only ]03+8#J
5、说明:删除新表 j3`#v3
drop table tabname G j^J pG
6、说明:增加一个列 `,XCD-R^
Alter table tabname add column col type
]3Z?Q
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 WVUa:_5{
7、说明:添加主键: Alter table tabname add primary key(col) c+:LDc3!Gb
说明:删除主键: Alter table tabname drop primary key(col) RO(~c-fV
8、说明:创建索引:create [unique] index idxname on tabname(col....) spIkXEK
删除索引:drop index idxname GMqeC
注:索引是不可更改的,想更改必须删除重新建。 @C]]VE
9、说明:创建视图:create view viewname as select statement 1oq5|2p
删除视图:drop view viewname tJ>|t hk
10、说明:几个简单的基本的sql语句 jU\vg;nr
选择:select * from table1 where 范围 ?;Ck]l#5ys
插入:insert into table1(field1,field2) values(value1,value2) Gq_rZo(@
删除:delete from table1 where 范围 $xRZU9+
更新:update table1 set field1=value1 where 范围 56 k89o
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! VPG+]>*
排序:select * from table1 order by field1,field2 [desc] 0J-]
总数:select count as totalcount from table1 {kGcZf3h
求和:select sum(field1) as sumvalue from table1 69#D,ME?
平均:select avg(field1) as avgvalue from table1 ^V]DQ%v"I
最大:select max(field1) as maxvalue from table1 #w\Bc\
最小:select min(field1) as minvalue from table1 j{00iA}
ck-ab0n
@Sb 86Ee
*k)v#;B
11、说明:几个高级查询运算词 i7g+8zd8d
%Q9
iR5?
NV 6kj=r
A: UNION 运算符 8YNii-pl
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ~^#F5w"
B: EXCEPT 运算符 #jdo54-
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 6( 1xU\x
C: INTERSECT 运算符 thWQU"z4
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 Hgs=qH
注:使用运算词的几个查询结果行必须是一致的。 z8W@N8IqC
12、说明:使用外连接 KUs\7Sb
A、left outer join: 3KFw0(S/
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 QJ{to%
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c m/W0vPM1
B:right outer join: |3\$\qa
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 7O6VnKl
C:full outer join: Z|&Y1k-h
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 t[Dg)adc
,VK! 3$;|
Ul@Jg
二、提升 TG ,T>'
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) d4@\5<
法一:select * into b from a where 1<>1 E[N5vG<
法二:select top 0 * into b from a f( (p\&y
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 8SmtEV[b3
insert into b(a, b, c) select d,e,f from b; TNYd_:j
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) hZ_0lX}
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 _2*Ryz
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. moO=TGG;F
4、说明:子查询(表名1:a 表名2:b) @Y2"=QVt
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) JN;92|x
5、说明:显示文章、提交人和最后回复时间 V. sIiE
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ~I^}'^Dbb
6、说明:外连接查询(表名1:a 表名2:b) 1eG@?~G
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 4
qdLH^dX
7、说明:在线视图查询(表名1:a ) {4u8~whLp
select * from (SELECT a,b,c FROM a) T where t.a > 1; d0(GE4+/
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 B/#tR^R
select * from table1 where time between time1 and time2 q0Rd^c
select a,b,c, from table1 where a not between 数值1 and 数值2 OE,uw2uaT
9、说明:in 的使用方法 !_{2\&
select * from table1 where a [not] in ('值1','值2','值4','值6') 4}nsW}jCc
10、说明:两张关联表,删除主表中已经在副表中没有的信息 jn+NX)9
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) /0 |niiI
11、说明:四表联查问题: E8]PV,#xY
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 ..... Op] L#<&T
12、说明:日程安排提前五分钟提醒 xgl~4
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 z0ULB?*"
13、说明:一条sql 语句搞定数据库分页 Zkn$D:
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 iy&*5U
14、说明:前10条记录 <a>\.d9#)7
select top 10 * form table1 where 范围 $,+'|_0yM
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) A/kRw'6
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) w3j51v` 0'
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 Z,~"`9>Ss
(select a from tableA ) except (select a from tableB) except (select a from tableC) IEb"tsel
17、说明:随机取出10条数据 K*&?+_v
:
select top 10 * from tablename order by newid() F^iv1b
18、说明:随机选择记录 gemjLuf
select newid() RfPRCIo
19、说明:删除重复记录 :v/6k
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) \<ohe w
20、说明:列出数据库里所有的表名 (`0dO8
select name from sysobjects where type='U' JM8s]&
21、说明:列出表里的所有的 dt NHj/\
select name from syscolumns where id=object_id('TableName') d\nBc6
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 D}Jhg`9
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type IbRy~
显示结果: %\=oy=f
type vender pcs cE
x$cZRMI
电脑 A 1 !ra CpL9;
电脑 A 1 mPHn &4
光盘 B 2 5u ED
光盘 A 2 ~<0!sE&y
手机 B 3 :P$I;YY=A
手机 C 3 5H_%inWM
23、说明:初始化表table1 'TPRGX~&
TRUNCATE TABLE table1 ,6[}qw)*
24、说明:选择从10到15的记录 Ck,.4@\tK
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc kqYvd]ss
{Kp<T
PPCZT3c=
=2%EIZ0oW
三、技巧 ^'8T9N@U
1、1=1,1=2的使用,在SQL语句组合时用的较多 {},rbQ
-
"where 1=1" 是表示选择全部 "where 1=2"全部不选, zdA:K25"
如: =l`xXma
if @strWhere !='' yVPkJ
begin #UREFwSL
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere *!De(lhEc
end x/$s:[0B#
else WWF#&)ti
begin T W?O
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' rN|c0N
end &k3'UN!&Ix
我们可以直接写成 k
fx<T
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere p9<OXeY
2、收缩数据库 LkFXUt ?
--重建索引 "AjtNL5
DBCC REINDEX ;S+c<MSl
DBCC INDEXDEFRAG \~xOdqF/
--收缩数据和日志 t`{^gt
DBCC SHRINKDB ]rM{\En
DBCC SHRINKFILE 1r}fnT<
3、压缩数据库 :)nn/[>fC
dbcc shrinkdatabase(dbname) zO>N 3pMv
4、转移数据库给新用户以已存在用户权限 eafy5vN[zX
exec sp_change_users_login 'update_one','newname','oldname' t#|E.G:=
go G)l[\6Dn
5、检查备份集 qx5X2@-;:
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' JH!qGV1
6、修复数据库 _C?<re3*
ALTER DATABASE [dvbbs] SET SINGLE_USER )@Yp;=l
GO f}bUuQrH-!
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ]>@;
2%YvY
GO `$`:PT\Zv4
ALTER DATABASE [dvbbs] SET MULTI_USER {+[~;ISL
GO %+$P<Rw7
7、日志清除 RIX0AE
SET NOCOUNT ON iUh_rX9A"
DECLARE @LogicalFileName sysname, Ms?V1
@MaxMinutes INT, S=lA^#'UdX
@NewSize INT . iq.H
USE tablename -- 要操作的数据库名 (5d~0
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ]
K7>R0
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ?Gl'-tV
@NewSize = 1 -- 你想设定的日志文件的大小(M) I=hgfo
-- Setup / initialize $JmL)r
DECLARE @OriginalSize int 8QYG"CA6/
SELECT @OriginalSize = size sTqy-^e7
FROM sysfiles =!xeki]|9
WHERE name = @LogicalFileName ~nb%w?vv
SELECT 'Original Size of ' + db_name() + ' LOG is ' + S6H=(l58
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + .Gl&K|/{j
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' :5?ti
FROM sysfiles 8 Oeg"d
WHERE name = @LogicalFileName TMG:fg&E~
CREATE TABLE DummyTrans eEJ8j_G
(DummyColumn char (8000) not null) #RJy
DECLARE @Counter INT, L&ws[8-
@StartTime DATETIME, ;:*o
P(9k
@TruncLog VARCHAR(255) {549&]/o
SELECT @StartTime = GETDATE(), L4sN)EI
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' h_ ]3L/
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 6K P!o
EXEC (@TruncLog) `.%;|"xR
-- Wrap the log if necessary. d8M"vd
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired FStE/2?
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ?OKm~ Ek
AND (@OriginalSize * 8 /1024) > @NewSize *6*#"#D
BEGIN -- Outer loop. MV$>|^'em
SELECT @Counter = 0 #`a-b<uz
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) $E|W|4N
BEGIN -- update #`GW7(M
INSERT DummyTrans VALUES ('Fill Log') G"MpA[a_
DELETE DummyTrans z$G?J+?J
SELECT @Counter = @Counter + 1 p%IR4f
END *ILS/`mdav
EXEC (@TruncLog) q30WUO;
END T-&CAD3 ,O
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ~N[hY1}X[
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + |k&.1NkZ
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' -7ct+3"J
FROM sysfiles /_,~dt
WHERE name = @LogicalFileName 6Ep ns s
DROP TABLE DummyTrans =[{Pw8['
SET NOCOUNT OFF q22cp&gmX
8、说明:更改某个表 kRiWNEw
exec sp_changeobjectowner 'tablename','dbo' }(E6:h;}~
9、存储更改全部表 ^&&dO*0{
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch /N%f78
Z
@OldOwner as NVARCHAR(128), o9wg<LP
@NewOwner as NVARCHAR(128) RW(AjDM
AS RU"w|Qu>pM
DECLARE @Name as NVARCHAR(128) Z(K [oUJx
DECLARE @Owner as NVARCHAR(128) NH'RU`U)
DECLARE @OwnerName as NVARCHAR(128) +7 F7Kh
DECLARE curObject CURSOR FOR
`4}!+fXQ
select 'Name' = name, 'VJMi5Y(-
'Owner' = user_name(uid) gn%#2:=pVu
from sysobjects Y1k/ngH
where user_name(uid)=@OldOwner {]<D"x;
order by name GJO/']k
OPEN curObject qsvUJU
FETCH NEXT FROM curObject INTO @Name, @Owner 3jS=
WHILE(@@FETCH_STATUS=0) <Dm6CH
BEGIN MP}H
5
if @Owner=@OldOwner pDkT_6Q
begin %\~;I73
set @OwnerName = @OldOwner + '.' + rtrim(@Name) h!K
B%4V
exec sp_changeobjectowner @OwnerName, @NewOwner mApn(&
end {+xUAmd
-- select @name,@NewOwner,@OldOwner u~s'<c+8_
FETCH NEXT FROM curObject INTO @Name, @Owner FG#j0#|*
END c+a f=ac
close curObject f{AgKW9"
deallocate curObject ,dVCbAS@
GO _9z/>e
10、SQL SERVER中直接循环写入数据 +=k?Dp[
declare @i int
=oQzL
set @i=1 rG\m]C3 E
while @i<30 CzvlZDo
begin m/eGnv;!
insert into test (userid) values(@i) ZC2C`S\xr
set @i=@i+1 6km
u'vw
end Q`vyDoF
小记存储过程中经常用到的本周,本月,本年函数 {t=Nnc15K
Dateadd(wk,datediff(wk,0,getdate()),-1) keJec`q=X
Dateadd(wk,datediff(wk,0,getdate()),6) %+I(S`}
Dateadd(mm,datediff(mm,0,getdate()),0) k2t?e:)3zr
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) w:Lu
Dateadd(yy,datediff(yy,0,getdate()),0) E<\\ 'VF
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) *<Ddn&_
上面的SQL代码只是一个时间段 oVq@M
Dateadd(wk,datediff(wk,0,getdate()),-1) DGd&x^C
Dateadd(wk,datediff(wk,0,getdate()),6) L//sJe
就是表示本周时间段. 5ef&Ih.3
下面的SQL的条件部分,就是查询时间段在本周范围内的: mlVv3mVyR<
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 8fe"#^"s R
而在存储过程中 g u|;C
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) _O!D*=I
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) "^XN"SUw