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。 xl(@C*.sC1
O.,3|
!gF9k8\Yr$
一、基础 :4:N f
1、说明:创建数据库 r> k-KdS
CREATE DATABASE database-name "g>.{E5
2、说明:删除数据库 )"Q*G/+2Ie
drop database dbname KzjC/1sd
3、说明:备份sql server c~0{s>
--- 创建 备份数据的 device {ox2Tg?
USE master M*sR3SZ
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' mMSh2B
--- 开始 备份 +vW)vS[
BACKUP DATABASE pubs TO testBack :w`3cwQ
4、说明:创建新表 Kv37s0|g
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) g:7,~}_}^
根据已有的表创建新表: j~E",7Q'
A:create table tab_new like tab_old (使用旧表创建新表) 20b<68h$:
B:create table tab_new as select col1,col2... from tab_old definition only Fk"Ee&H)(
5、说明:删除新表 ~
Vw9
drop table tabname RBwO+J53y
6、说明:增加一个列 LJFG0 W
Alter table tabname add column col type Ej=3/RBsV
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。 Tlq-m2]
7、说明:添加主键: Alter table tabname add primary key(col)
\(~wZd
说明:删除主键: Alter table tabname drop primary key(col) !ErH~<f%K
8、说明:创建索引:create [unique] index idxname on tabname(col....) 6KHN&P
删除索引:drop index idxname !8
-oR6/$%
注:索引是不可更改的,想更改必须删除重新建。 4jNG^@O
9、说明:创建视图:create view viewname as select statement T f4tj!t-
删除视图:drop view viewname <q
(z>*-e
10、说明:几个简单的基本的sql语句 p =(@3%k
选择:select * from table1 where 范围 a(IY\q[Wh
插入:insert into table1(field1,field2) values(value1,value2) *T`-|H*6@
删除:delete from table1 where 范围 SJ?6{2^
更新:update table1 set field1=value1 where 范围 yF13Of^l./
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! :O-iykXyI
排序:select * from table1 order by field1,field2 [desc] 7 <9yH:1
总数:select count as totalcount from table1 D}3T|N
求和:select sum(field1) as sumvalue from table1 UlcH%pxTt1
平均:select avg(field1) as avgvalue from table1 GsQ*4=C
最大:select max(field1) as maxvalue from table1 ,](:<A)W&
最小:select min(field1) as minvalue from table1 _;1}x%4v
izgp*M,
@{hd{>K*
`F t]MR
11、说明:几个高级查询运算词 ~]HN9R^&
2)X4y"l
vI1i,x#i
A: UNION 运算符 ^EELaG
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。 "9!d]2.-Vk
B: EXCEPT 运算符 Rk6deI]
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。 ({s6eqMhDd
C: INTERSECT 运算符 S4UM|`
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。 '1?\/,em
注:使用运算词的几个查询结果行必须是一致的。 >Dw~POMy
12、说明:使用外连接 [XVEBA4GI
A、left outer join: wh6yPVVF/
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。 Q=mI9
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 _"@CGXu
B:right outer join: ` x8J
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。 xu5ia|gYz7
C:full outer join: dU) ]:>Uz
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。 a"N4~?US
{\H/y c|@
1CU>L[W)
二、提升 ~{hxR)x9
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) aNcd`
$0
法一:select * into b from a where 1<>1 S$TmZk=
法二:select top 0 * into b from a fyTAou6hI
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Vd^g9
insert into b(a, b, c) select d,e,f from b; E 99hlY~1:
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) 5|3e&
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 M_v?9L
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. C+[%7vF1
4、说明:子查询(表名1:a 表名2:b) Kt@M)#
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) ">f erhN9
5、说明:显示文章、提交人和最后回复时间 @"a6fn
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 1 `^Rdi0
6、说明:外连接查询(表名1:a 表名2:b) ]aP=Ks%
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c <8,o50`B
7、说明:在线视图查询(表名1:a ) dzLQI}89+k
select * from (SELECT a,b,c FROM a) T where t.a > 1; \B F*m"lz
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 4iAZ+l5&
select * from table1 where time between time1 and time2 'c2W}$q
select a,b,c, from table1 where a not between 数值1 and 数值2 XU!2YO)t;!
9、说明:in 的使用方法 L86n}+
P\
select * from table1 where a [not] in ('值1','值2','值4','值6') ]]7mlQ
10、说明:两张关联表,删除主表中已经在副表中没有的信息 O[tvR:Nh
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Q!-
0xlx
11、说明:四表联查问题: P-F)%T[
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 ..... W} WI; cI
12、说明:日程安排提前五分钟提醒 A.<H>=Z#O
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 H]Hv;fcC
13、说明:一条sql 语句搞定数据库分页 fjvN$NgVs
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 r/pH_@
14、说明:前10条记录 mxor1P#|
select top 10 * form table1 where 范围 !It`+0S
b
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.) %CWPbk^
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) D\IjyZ-O
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 SJD@&m%?[
(select a from tableA ) except (select a from tableB) except (select a from tableC) 9T#;,{VQ
17、说明:随机取出10条数据 P96pm6H_;
select top 10 * from tablename order by newid() +]=e;LN $0
18、说明:随机选择记录 EY*(Bw
select newid() fYKO J5f
19、说明:删除重复记录 C{TA.\
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) hxce\OuU0h
20、说明:列出数据库里所有的表名 %ZHP2j
%~
select name from sysobjects where type='U' "KcA
21、说明:列出表里的所有的 n>@oBG)!
select name from syscolumns where id=object_id('TableName') >WY#4
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。 21k5I #U
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 ga?*DI8w
显示结果: d%l{V6
type vender pcs ^u3V
E
电脑 A 1 OL4z%mDZi
电脑 A 1 Y5fLmPza
光盘 B 2 {U&.D
[{&
光盘 A 2 SG6sw]x
手机 B 3 ySI~{YVM
手机 C 3 Mq';S^
23、说明:初始化表table1 AwQ?l(iZ"p
TRUNCATE TABLE table1 %Uz(Vd#K
24、说明:选择从10到15的记录 bn
|zl!Pq
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc R<B7K?SxV~
7GDHz.IX
kdGT{2u
,3nN[)dk
三、技巧 2<M= L1\
1、1=1,1=2的使用,在SQL语句组合时用的较多 Df3rV '/~
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 6 uKTGc4
如: &89oO@5
if @strWhere !='' 0uBl>A7qhn
begin 2NB L}x
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere i<pk6rO1
end mKYeD%Pm*
else ve&zcSeb
begin O%r; 5kP
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' &=4(l|wcg
end DBLO|&2!z[
我们可以直接写成 RT%pDym\
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere sXNb }gJ
2、收缩数据库 >>[G1
--重建索引 vTv]U5%:>%
DBCC REINDEX )V!dBl"Gq
DBCC INDEXDEFRAG 4H@Wc^K
--收缩数据和日志 |HZTN"
DBCC SHRINKDB pmX#E
DBCC SHRINKFILE EI\9_}@,
3、压缩数据库 mFHH515
dbcc shrinkdatabase(dbname) `5H$IP1XhA
4、转移数据库给新用户以已存在用户权限 `"%T=w
exec sp_change_users_login 'update_one','newname','oldname' ;E'"Ks[GH
go 4lZ$;:Jg
5、检查备份集 9{:O{nl
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' eI@
q|"U
6、修复数据库 ,^S@EDq
ALTER DATABASE [dvbbs] SET SINGLE_USER *b];|n{
GO iOG[>u0h
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ?&Pg2]g<
GO *cyeO*
ALTER DATABASE [dvbbs] SET MULTI_USER qc-mGmom L
GO OQ9x*TmK
7、日志清除 n-DVT;y
SET NOCOUNT ON : }`-B0
DECLARE @LogicalFileName sysname, -,["c9'3
@MaxMinutes INT, @^uH`mc
@NewSize INT 8uA,iYD
USE tablename -- 要操作的数据库名 O@YTAT&d#
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Z{H5oUk
@MaxMinutes = 10, -- Limit on time allowed to wrap log. bGorH=pb5R
@NewSize = 1 -- 你想设定的日志文件的大小(M) Hk|0HL
-- Setup / initialize $-On~u0g
DECLARE @OriginalSize int F]9nB3:W
SELECT @OriginalSize = size &d'Awvy0
FROM sysfiles &N;-J2M
WHERE name = @LogicalFileName ] Eh}L
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ><=gV~7lx
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 1
E22R
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB'
eAqz3#_My
FROM sysfiles @u1zB:
WHERE name = @LogicalFileName v(pmIb{
CREATE TABLE DummyTrans ]^6c8sgnR
(DummyColumn char (8000) not null) o-o'z'9
DECLARE @Counter INT, Wq^qpN)5Y
@StartTime DATETIME, w^]6w\p
@TruncLog VARCHAR(255) d:F @a
SELECT @StartTime = GETDATE(), hUm'8)OJ
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' d[;.r
DBCC SHRINKFILE (@LogicalFileName, @NewSize) w4fW<ISg
EXEC (@TruncLog) +kFxi2L6
-- Wrap the log if necessary. ,6r{VLN
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired gkHNRAL
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) cCR+D.F
AND (@OriginalSize * 8 /1024) > @NewSize w}CmfR
BEGIN -- Outer loop. Ka,^OW}<%q
SELECT @Counter = 0 hI( SOsKs
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) M'!U<Y
-
BEGIN -- update I<A6Z&*un
INSERT DummyTrans VALUES ('Fill Log') is/scv<
DELETE DummyTrans *OyHHq|>q
SELECT @Counter = @Counter + 1 QFIL)'K
END h;j IYxj
EXEC (@TruncLog) ){Ob,LEU&
END "kc/J*u-3
SELECT 'Final Size of ' + db_name() + ' LOG is ' + M|] "W
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + HEGKX]
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' P bQk<"J1
FROM sysfiles PdVfO8-
WHERE name = @LogicalFileName 9+keX{/c
DROP TABLE DummyTrans v
36%Pj`
SET NOCOUNT OFF |^9BA-nA
8、说明:更改某个表 ;m2<eS`o'
exec sp_changeobjectowner 'tablename','dbo' rSYi<ku
9、存储更改全部表 n>'Kp T9|
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch <G*nDFWf
@OldOwner as NVARCHAR(128), ooV*I|wcI
@NewOwner as NVARCHAR(128) ;vb8G$
AS `g,8-
DECLARE @Name as NVARCHAR(128) G-T0f
DECLARE @Owner as NVARCHAR(128) 6eokCc"o
DECLARE @OwnerName as NVARCHAR(128) 5K?}}Frrt`
DECLARE curObject CURSOR FOR 5#QXR+
T
select 'Name' = name, D0N9Ksq
'Owner' = user_name(uid) \);4F=h}f
from sysobjects 3 LdQ]S
where user_name(uid)=@OldOwner X*L;.@xA
order by name &
=/
OPEN curObject C
XHy.&Vt
FETCH NEXT FROM curObject INTO @Name, @Owner 8?FbtBAn
WHILE(@@FETCH_STATUS=0) HQ{JwW!m
BEGIN ^S6u<,
if @Owner=@OldOwner PpsIhMq@
begin xB !6_VlB
set @OwnerName = @OldOwner + '.' + rtrim(@Name) wK}\_2?
exec sp_changeobjectowner @OwnerName, @NewOwner UswZG^Wh
end tBct
-- select @name,@NewOwner,@OldOwner t
R6
+G
FETCH NEXT FROM curObject INTO @Name, @Owner JBnKK
END {%#)5l)
close curObject "4%"&2L
deallocate curObject *]i!fzI']
GO 1$*%" 5a
10、SQL SERVER中直接循环写入数据 b2@VxdFN
declare @i int =rR~ `
set @i=1 DvM5 k
while @i<30 98.>e
begin 21(p|`X
insert into test (userid) values(@i) sFBneBub
set @i=@i+1 &[hLzlrg
end mYU9
trHV
小记存储过程中经常用到的本周,本月,本年函数 b]a@
Dateadd(wk,datediff(wk,0,getdate()),-1) _uJ"m8Tl
Dateadd(wk,datediff(wk,0,getdate()),6) a[2vjFf#C
Dateadd(mm,datediff(mm,0,getdate()),0) +S))3 5N[
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) jVH|uX"M5Y
Dateadd(yy,datediff(yy,0,getdate()),0) Nl')l"
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) !cGDy/|
上面的SQL代码只是一个时间段 "HYQqNj?Z
Dateadd(wk,datediff(wk,0,getdate()),-1) rS1fK1dys
Dateadd(wk,datediff(wk,0,getdate()),6) *Y@nVi
就是表示本周时间段. RyRpl*^
下面的SQL的条件部分,就是查询时间段在本周范围内的: b$eXFi/
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) t^ZV|s 1
而在存储过程中 }y%oT
P&
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) [{r}u
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ai*f
F