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。 AHRJ7l;a
gVrQAcJj
J$Z=`=]t+
一、基础 2]1u0-M5L
1、说明:创建数据库 U.KQjBi
CREATE DATABASE database-name rUpe ;c
2、说明:删除数据库 baBBn%_V
drop database dbname W#S8 2
3、说明:备份sql server l% T4:p4e
--- 创建 备份数据的 device RWc<CQcL"
USE master #~!"`B?#*
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' `J1HQ!Z
--- 开始 备份 E7t;p)x
BACKUP DATABASE pubs TO testBack L8 L1_
4、说明:创建新表 ;xZjt4M1
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) HcgvlFb
根据已有的表创建新表: _]-4d_&3(
A:create table tab_new like tab_old (使用旧表创建新表) C,An\lsT
B:create table tab_new as select col1,col2... from tab_old definition only nq)F$@
5、说明:删除新表 z@yTkH_
drop table tabname G@.MP|
2
6、说明:增加一个列 x2rAB5r6
Alter table tabname add column col type < cvh1~>(
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。 0V4B Q:v
7、说明:添加主键: Alter table tabname add primary key(col) Lm
TFvZ
说明:删除主键: Alter table tabname drop primary key(col) &^r>Q`u
8、说明:创建索引:create [unique] index idxname on tabname(col....) OvtE)ul@
删除索引:drop index idxname DMM<,1
注:索引是不可更改的,想更改必须删除重新建。 51SmoFbMz
9、说明:创建视图:create view viewname as select statement f#=c=e-A
删除视图:drop view viewname P.}d@qD{)
10、说明:几个简单的基本的sql语句 J#zr50@@
选择:select * from table1 where 范围 3''Sx8p
插入:insert into table1(field1,field2) values(value1,value2) ]1|P|Jp
删除:delete from table1 where 范围 _dJ(h6%3
更新:update table1 set field1=value1 where 范围 Nob(D'vSr
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 64<;6*
排序:select * from table1 order by field1,field2 [desc] BDTL5N
总数:select count as totalcount from table1 aYWWln
求和:select sum(field1) as sumvalue from table1 }(oeNPM8
平均:select avg(field1) as avgvalue from table1 s
V_(9@b
最大:select max(field1) as maxvalue from table1 "j@\a)a
最小:select min(field1) as minvalue from table1 flsejj$
)h8}{*
bC/":+s& p
!cwZ*eM
11、说明:几个高级查询运算词 qI+2,6
sGI
Upe}9xf
]mTBD<3\
A: UNION 运算符 1u
9hA~rj
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。 '+`[)w
B: EXCEPT 运算符 c+ oi8G
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。 <s9?9^!!V^
C: INTERSECT 运算符 cJ;Nh>ey
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。 k, HC"?K
注:使用运算词的几个查询结果行必须是一致的。 j*jUcD*
12、说明:使用外连接 *.DC(2:o!
A、left outer join: ilA45@
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。 0NXH449I=
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 }yz>(Pq
B:right outer join: V
~C$| +>e
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 ffZ~r%25{
C:full outer join: 5E&#Kh(I
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 .T|
}rB<c
0zaK&]oY0
A&Y5z[p
二、提升 ;mkkaW,D*
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) x HRSzYn$
法一:select * into b from a where 1<>1 bGPE0}b
法二:select top 0 * into b from a l/&.H F
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 5*AXL.2ih
insert into b(a, b, c) select d,e,f from b; eTiTS*`u
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) [3Pp
NCY
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 [nTI\17iA
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. GJ+ ^t
4、说明:子查询(表名1:a 表名2:b) P {TJ$
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) cHs3:F~~
5、说明:显示文章、提交人和最后回复时间 8xAV[i
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b `(e :H
6、说明:外连接查询(表名1:a 表名2:b) /yOx=V
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c /wV|;D^ )
7、说明:在线视图查询(表名1:a ) Cn{Hk)6
select * from (SELECT a,b,c FROM a) T where t.a > 1; l":W@R
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 Ri. tA
select * from table1 where time between time1 and time2 mj~:MCC
select a,b,c, from table1 where a not between 数值1 and 数值2 LeKovt%
9、说明:in 的使用方法 &*C5Nnlv
select * from table1 where a [not] in ('值1','值2','值4','值6') "Ms;sdjg}&
10、说明:两张关联表,删除主表中已经在副表中没有的信息 W>K^55'
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) E}@C4pS
11、说明:四表联查问题: "
kDiK`i
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 ..... J2YQdCL
12、说明:日程安排提前五分钟提醒 jD:
N)((
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Q7BbST+
13、说明:一条sql 语句搞定数据库分页 fB+L%+mr8
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 YW7W6mWspS
14、说明:前10条记录 #z\ub5um
select top 10 * form table1 where 范围 ?'a8QJo
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.) JMb_00r
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) oQ$yr^M
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 p0+^wXi)
(select a from tableA ) except (select a from tableB) except (select a from tableC) RB 5SK#z
17、说明:随机取出10条数据 SmRlZ!%e
select top 10 * from tablename order by newid() XYEwn_Y
18、说明:随机选择记录 IG781:,/
select newid() !wAT`0<94F
19、说明:删除重复记录 |=?#Xbxz
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) NAbVH{*\U
20、说明:列出数据库里所有的表名 dbI>\khI
select name from sysobjects where type='U' .tngN<f
21、说明:列出表里的所有的 ~zVxprEf_
select name from syscolumns where id=object_id('TableName')
hAGHb+:
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 YH&=cI@
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type z/@_?01T=
显示结果: }A#IBqf5
type vender pcs g@.$P>Bh
电脑 A 1 y.r N(
电脑 A 1 (eHyas %X
光盘 B 2 Vwkvu&4
光盘 A 2 /:{%X(8
手机 B 3 i+_LKHQN
手机 C 3 }3pM,.
23、说明:初始化表table1 ?,} u6tH
TRUNCATE TABLE table1 <`H0i*|Ued
24、说明:选择从10到15的记录 QV;o9j
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc e+
xQ\LH
Sj9fq*
YOCEEh?
K1&
QAXyP
三、技巧 1!#85SMx
1、1=1,1=2的使用,在SQL语句组合时用的较多 yI0bSu<j-
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 55[ 4)*
如: _(W@FS
if @strWhere !='' dG\wW@}J
begin jLVJ+mu
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 1W^hPY
end 6{Wo5O{!\
else f:c'j`
begin aSL`yuXu
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 1+l 8%G=hB
end u-_r2U
我们可以直接写成 Hbm 4oYN
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ?J}Q&p.
2、收缩数据库 $( hT{C,K
--重建索引 $] 6u#5
DBCC REINDEX lj4Fg*/Yn
DBCC INDEXDEFRAG Zt=|q$"
--收缩数据和日志 5]xuU.w'
DBCC SHRINKDB 5&]5*;Bv J
DBCC SHRINKFILE mH*ldf;J;=
3、压缩数据库 %,>z`D,Hg
dbcc shrinkdatabase(dbname) 20:F$d
4、转移数据库给新用户以已存在用户权限 Lvk}% ,S8t
exec sp_change_users_login 'update_one','newname','oldname' .sMs_ 5D
go s**<=M GK
5、检查备份集 36d nS>4
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Y.:R-|W
6、修复数据库 h2l;xt
ALTER DATABASE [dvbbs] SET SINGLE_USER $Y/9SD
GO 0;Z|:\P\=
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK <izQ]\kL
GO &2'-v@kK
ALTER DATABASE [dvbbs] SET MULTI_USER tvkdNMyX%9
GO
-m@o\9Ic
7、日志清除 h`[$
Bp
SET NOCOUNT ON .*O*@)}Ud
DECLARE @LogicalFileName sysname, L/3A g*
]
@MaxMinutes INT, .RD<]BxJ
@NewSize INT )6|L]'dsZ
USE tablename -- 要操作的数据库名 qi-XNB`b
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 m|*B0GW
@MaxMinutes = 10, -- Limit on time allowed to wrap log. z;OYPGvkw
@NewSize = 1 -- 你想设定的日志文件的大小(M) Rr) 5[
-- Setup / initialize B2`S0 H
DECLARE @OriginalSize int }gp@0ri%5
SELECT @OriginalSize = size B(Sy.n
FROM sysfiles WT
*"V<Z
WHERE name = @LogicalFileName R@e'=z[%1
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^-o{3Q(w
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + /:dLqyQ_V
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' l|5 h
FROM sysfiles m</m9h8
WHERE name = @LogicalFileName e`*}?N4d
CREATE TABLE DummyTrans ]#/nn),Z
(DummyColumn char (8000) not null) +UzQJt/>>
DECLARE @Counter INT, W4^L_p>Tm^
@StartTime DATETIME, 6FS%9.Ws
@TruncLog VARCHAR(255) kY0HP a
SELECT @StartTime = GETDATE(), XS<>0YM
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' $vn6%M[
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 3JazQU
EXEC (@TruncLog) 2e48L677-
-- Wrap the log if necessary. d;i|s[6ds`
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired K<JzIuf&
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ts]e M1;
AND (@OriginalSize * 8 /1024) > @NewSize FU`(mQ*Yd
BEGIN -- Outer loop. | /.J{=E0K
SELECT @Counter = 0 5Qgu:)}
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) AFLtgoXn:
BEGIN -- update ?K1B^M=8
INSERT DummyTrans VALUES ('Fill Log') dFg>uo
DELETE DummyTrans tV}!_
SELECT @Counter = @Counter + 1 JK,MK|
END #w$Y1bjn
EXEC (@TruncLog) V&Y`?Edc
END `Rq=:6U;3
SELECT 'Final Size of ' + db_name() + ' LOG is ' + _nGx[1G( 5
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + rPxRGoR
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' _&KqmQ8$7
FROM sysfiles
:e1h!G
WHERE name = @LogicalFileName pEyZH!W
DROP TABLE DummyTrans I&PJ[U#~a
SET NOCOUNT OFF YAi-eL67l
8、说明:更改某个表 y\Wn:RR1 [
exec sp_changeobjectowner 'tablename','dbo' h>Kx
9、存储更改全部表 1"
'3/MFQ8
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch *v<f#hB"
@OldOwner as NVARCHAR(128), kk4 |4
@NewOwner as NVARCHAR(128) #G9
W65 f
AS sz7*x{E
DECLARE @Name as NVARCHAR(128) kc'$4 J4Tw
DECLARE @Owner as NVARCHAR(128) !j~wAdHk
DECLARE @OwnerName as NVARCHAR(128) DP_b9o
\5
DECLARE curObject CURSOR FOR L!f~Am:#
select 'Name' = name, vHaM yA-
'Owner' = user_name(uid) Bfb~<rs[
from sysobjects ct+F\:e
where user_name(uid)=@OldOwner R'c*CLaiE
order by name q~{)
{t;
OPEN curObject %G?@Hye3
FETCH NEXT FROM curObject INTO @Name, @Owner *)^6'4=
WHILE(@@FETCH_STATUS=0) Y,L`WeQY.
BEGIN 4P{|H
if @Owner=@OldOwner 8 t+eu O
begin ;`AB-
set @OwnerName = @OldOwner + '.' + rtrim(@Name) X4 !93
exec sp_changeobjectowner @OwnerName, @NewOwner UB~K/r`.|
end e02Hf{eOfw
-- select @name,@NewOwner,@OldOwner .ARYCTyG
FETCH NEXT FROM curObject INTO @Name, @Owner F`=p/IAJK
END 0d2P
close curObject S!K<kn`E3
deallocate curObject U1\EwBK8*T
GO 3Tr,waV
10、SQL SERVER中直接循环写入数据 ammi4k/
declare @i int fe .=Z&
set @i=1 c!w[)>v
while @i<30 }G4I9Py
begin "&L8d(ZuA
insert into test (userid) values(@i) ,%!m%+K9a
set @i=@i+1 ?;~!C2Zs
end N2:Hdu:
小记存储过程中经常用到的本周,本月,本年函数 `
w;Wud'*<
Dateadd(wk,datediff(wk,0,getdate()),-1) 14$%v;Su4
Dateadd(wk,datediff(wk,0,getdate()),6) xd?=#d
Dateadd(mm,datediff(mm,0,getdate()),0) G1|1Z5r
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) i0M6;W1T
Dateadd(yy,datediff(yy,0,getdate()),0) pl8b&bLzi
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) %:26v
上面的SQL代码只是一个时间段 d+n2
c`i
Dateadd(wk,datediff(wk,0,getdate()),-1) {lK2yi
Dateadd(wk,datediff(wk,0,getdate()),6) HDm]njF%qQ
就是表示本周时间段. 2gWR2 H@
下面的SQL的条件部分,就是查询时间段在本周范围内的: lHiWzt
u
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ~[H8R|j "
而在存储过程中 h!tpi`8\z
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) &%J{uRp
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) , ['}9:f9