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。 ^n]?!BdU
\v9<L'NP)
HZ2 zL17
一、基础 Q([g1?F9*
1、说明:创建数据库 V|0UwS\n
CREATE DATABASE database-name pk=z<OTb
2、说明:删除数据库 {24Pv#ZG#^
drop database dbname C$B?|oUJc
3、说明:备份sql server |om3* ]7
--- 创建 备份数据的 device U`'w{~"D%
USE master w@f_TG"Vt
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' `V0]t_*D
--- 开始 备份 [
06B)|s
BACKUP DATABASE pubs TO testBack 6Ue6b$xE
4、说明:创建新表 ?Z7C0u#wd
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) |y=D^NTG
根据已有的表创建新表: WI'csM;M#
A:create table tab_new like tab_old (使用旧表创建新表) 1$2Rs-J
B:create table tab_new as select col1,col2... from tab_old definition only veE8
N~0N.
5、说明:删除新表 K<_H`k*x
drop table tabname J5rR?[i{
6、说明:增加一个列 ||,;07
Alter table tabname add column col type CblL1 q8
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 h;unbz
7、说明:添加主键: Alter table tabname add primary key(col) Ri-wbYFaP
说明:删除主键: Alter table tabname drop primary key(col) EGMcU|yL
8、说明:创建索引:create [unique] index idxname on tabname(col....) T@HozZ
删除索引:drop index idxname 1X9sx&5H
注:索引是不可更改的,想更改必须删除重新建。 -s!PO;qm
9、说明:创建视图:create view viewname as select statement ,!py
n<_
删除视图:drop view viewname wYawG$@_
10、说明:几个简单的基本的sql语句 |$ 0/:*
选择:select * from table1 where 范围 i\eykYc,
插入:insert into table1(field1,field2) values(value1,value2) 9_/1TjrDN
删除:delete from table1 where 范围 -jw=Iyv
更新:update table1 set field1=value1 where 范围 (c_hX(
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! G`W+m*[U+M
排序:select * from table1 order by field1,field2 [desc] =UP)b9*h
总数:select count as totalcount from table1 BZ T%+s;u9
求和:select sum(field1) as sumvalue from table1 4'8.f5
平均:select avg(field1) as avgvalue from table1 J/*[wj
最大:select max(field1) as maxvalue from table1 V7v,)a" L
最小:select min(field1) as minvalue from table1 K^vMIo h
_0`O}
DpR%s",Q
Q&\k"X 1
11、说明:几个高级查询运算词 *Ee# x!O
Q'Tn+}B&
#WG(V%f]
A: UNION 运算符 \dMsv1\
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。 @'y"D
B: EXCEPT 运算符 i
xyjl[G
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。 *]=)mM#
C: INTERSECT 运算符 x/<.?[A
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。 0.5_,an3
注:使用运算词的几个查询结果行必须是一致的。 ),Rj@52l
12、说明:使用外连接 YD%Kd&es
A、left outer join: mB~&nDU
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。 M>#{~zr
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 EIfrZg7R
B:right outer join: xVPGlU
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。 -d~'tti
C:full outer join: :[&X*bw[
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。 1XKk~G"D
ublY!Af
l9h;dI{6
二、提升 ^s*} 0
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ;FBc^*q
法一:select * into b from a where 1<>1 y()( 8L
法二:select top 0 * into b from a >seB["C
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ;a`X|N9
insert into b(a, b, c) select d,e,f from b; U{Z>y?V/
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) *GhRU5
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ;~J~g#
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. P.:T
zk6
4、说明:子查询(表名1:a 表名2:b) Ymu=G3-
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) K36B9<F
5、说明:显示文章、提交人和最后回复时间 oX~CTunP
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Ln|${c
6、说明:外连接查询(表名1:a 表名2:b) 'Ap5Aq
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ,Mc2dhq
7、说明:在线视图查询(表名1:a ) ~}*;Ko\
select * from (SELECT a,b,c FROM a) T where t.a > 1; ;GSJnV
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 @El<"\
select * from table1 where time between time1 and time2 jHCKV
select a,b,c, from table1 where a not between 数值1 and 数值2 wrU[#g,uvr
9、说明:in 的使用方法 A2d2V**Z
select * from table1 where a [not] in ('值1','值2','值4','值6') o{p_s0IX;S
10、说明:两张关联表,删除主表中已经在副表中没有的信息 3#[I_
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) [\1l4C
11、说明:四表联查问题: v"+EBfx
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... v_0!uT5~NE
12、说明:日程安排提前五分钟提醒 G
m! ]
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 kVv
<tw
13、说明:一条sql 语句搞定数据库分页 VHCzlg
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 D$E9%'ir
14、说明:前10条记录 [B`P]}gL:
select top 10 * form table1 where 范围 P;&p[[7
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.) Fr3t[:D
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) /p0LtUMu
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 ;[ueNP%*y|
(select a from tableA ) except (select a from tableB) except (select a from tableC) XD }_9p
17、说明:随机取出10条数据
YPnJldVn
select top 10 * from tablename order by newid() 0)V-|v`
18、说明:随机选择记录 &NeYKh?
select newid() P*Sip?tdE
19、说明:删除重复记录 u$8MVP
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) a HL '(<
20、说明:列出数据库里所有的表名 [uQZD1<q
select name from sysobjects where type='U' 22~X~=
21、说明:列出表里的所有的 z&,sm5Lb
select name from syscolumns where id=object_id('TableName') /ASI0h
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。 L"%eQHEC&
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 W%K8HAP "
显示结果: g}QTZT8
type vender pcs @(fY4]K
电脑 A 1 `+c9m^
电脑 A 1 Lu.tRZ`$38
光盘 B 2 C)p<M H<
光盘 A 2 gEHfsR=D6
手机 B 3 Vj`s_IPY
手机 C 3 os^SD&hL
23、说明:初始化表table1 }AZx/[k
|z
TRUNCATE TABLE table1 Yka&Kkw
24、说明:选择从10到15的记录 +\vY; !^
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 7Sq{A@ET
I} fcFL8
~{Rt4o _W
@aN=U=
三、技巧 i}F;fWZ`
1、1=1,1=2的使用,在SQL语句组合时用的较多 *Ne2l`!1m
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 4eL54).1O
如: ,h.Jfo54,
if @strWhere !='' TxxB0
begin RdvTtXg
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere G:C6`uiy`
end 3nC#$L-
else | 4oM+n;Y
begin AnE_<sPA
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' @j2*.ee
end hIo S#]
我们可以直接写成 9iddanQA
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere "q>I?UcZ
2、收缩数据库 Sb9=$0%\
--重建索引 ]op^dW1;0_
DBCC REINDEX r,@X>_}
DBCC INDEXDEFRAG A.C278^O8
--收缩数据和日志 6O@ ^`T
DBCC SHRINKDB mImbS)V
DBCC SHRINKFILE +;wqX]SD &
3、压缩数据库 QD;f~fZ
dbcc shrinkdatabase(dbname) Ed0>R<jR9
4、转移数据库给新用户以已存在用户权限 kPX2e h
exec sp_change_users_login 'update_one','newname','oldname' Q'Kik5I
go 7}tZ?vD
5、检查备份集 g=g.GpFt
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' (06Vcqg
6、修复数据库 CNRU"I+jU
ALTER DATABASE [dvbbs] SET SINGLE_USER E%\7Uo-
GO 1s}NQ3
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK l88a#zUQDN
GO Rp`_Grcd
ALTER DATABASE [dvbbs] SET MULTI_USER !ga(L3vf
GO #C,f/PXfaB
7、日志清除 p-'6_\F.Ke
SET NOCOUNT ON 7fW=5wc
DECLARE @LogicalFileName sysname, FH`'1iVH
@MaxMinutes INT, R|)2Dg
@NewSize INT .xLF}{u
USE tablename -- 要操作的数据库名 [N95.aD
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ? __aVQ7
@MaxMinutes = 10, -- Limit on time allowed to wrap log. <`p75B
@NewSize = 1 -- 你想设定的日志文件的大小(M) u_6BHsU
-- Setup / initialize EB29vHAt~
DECLARE @OriginalSize int D _bkUR1
SELECT @OriginalSize = size \Ul.K!b7
FROM sysfiles MCi` TXr
WHERE name = @LogicalFileName ^L8Wn6s'
SELECT 'Original Size of ' + db_name() + ' LOG is ' + |:(23O
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + )p!*c,
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' /\-2l+y>J
FROM sysfiles Z4HA94
WHERE name = @LogicalFileName N7~)qqb
CREATE TABLE DummyTrans /J[H5uA
(DummyColumn char (8000) not null) mP)3cc5T
DECLARE @Counter INT, vlPl(F1
@StartTime DATETIME, U7]<U-.&
@TruncLog VARCHAR(255) pVV}1RDa
SELECT @StartTime = GETDATE(), 5U)ab3:
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' dDqr
B-G
DBCC SHRINKFILE (@LogicalFileName, @NewSize) >St.c
EXEC (@TruncLog) { p!_-sL
-- Wrap the log if necessary. L8bI0a]r"*
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired _^6|^PT.
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) p- "Z'$A`
AND (@OriginalSize * 8 /1024) > @NewSize
e'~-`Z9-)
BEGIN -- Outer loop. Z@uTkqG)
SELECT @Counter = 0 " xDx/d8B
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) @q> ktE_
BEGIN -- update a@fE46o6<
INSERT DummyTrans VALUES ('Fill Log') c?!YFm
DELETE DummyTrans 2/v35| ?
SELECT @Counter = @Counter + 1 S]e j=6SP
END uq !;
EXEC (@TruncLog) IU Y> ih
END XOysgX0g
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 49+ >f
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 9TVB<}0G
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Sc1+(z
FROM sysfiles N+CXOI=6x
WHERE name = @LogicalFileName a>wfhmr
DROP TABLE DummyTrans *'9)H0
SET NOCOUNT OFF ioC@n8_[G
8、说明:更改某个表 .7
(DxN
exec sp_changeobjectowner 'tablename','dbo'
SwdC,
9、存储更改全部表 )p$\gwr=2
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch $?FS00p*|X
@OldOwner as NVARCHAR(128), zVM4BT(
@NewOwner as NVARCHAR(128) tmO;:n<N
AS <u/a`E?
DECLARE @Name as NVARCHAR(128) I86e&"40
DECLARE @Owner as NVARCHAR(128) pOqGAD{D$
DECLARE @OwnerName as NVARCHAR(128) rQ9*J
DECLARE curObject CURSOR FOR p+, 1Fi
select 'Name' = name, Y]C;T
'Owner' = user_name(uid) BRQ"A,
from sysobjects Vh"MKJ'R^
where user_name(uid)=@OldOwner j~M#Ss-H8
order by name rkxW UDl
OPEN curObject `1nRcY
FETCH NEXT FROM curObject INTO @Name, @Owner z>4D~HX
WHILE(@@FETCH_STATUS=0) oi7
3YOB
BEGIN K*_-5e
if @Owner=@OldOwner \Ut6;
begin mfXD1]<.
set @OwnerName = @OldOwner + '.' + rtrim(@Name) *;<e
'[Y7f
exec sp_changeobjectowner @OwnerName, @NewOwner {IJ-4>
end 7t'(`A6t/
-- select @name,@NewOwner,@OldOwner CV '&4oq
FETCH NEXT FROM curObject INTO @Name, @Owner G49Ng|qn
END d
i!"IQAvK
close curObject |<sf:#YzY&
deallocate curObject _ 1sP.0 t
GO (nGkZ}p
10、SQL SERVER中直接循环写入数据 :`D'jF^S
declare @i int h~ $&
set @i=1 _3|6ZO
while @i<30 f2NA=%\
begin /T,zZ9=
insert into test (userid) values(@i) >A3LA3(
c
set @i=@i+1 UmJUt|
end l{8CISO*
小记存储过程中经常用到的本周,本月,本年函数 L#n}e7Y9
Dateadd(wk,datediff(wk,0,getdate()),-1) 9hy'DcSy,
Dateadd(wk,datediff(wk,0,getdate()),6) h%'
N hV
Dateadd(mm,datediff(mm,0,getdate()),0) zt?h^zf}
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) D -6
Dateadd(yy,datediff(yy,0,getdate()),0) V{!lk]p}a
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 0{Bf9cH
上面的SQL代码只是一个时间段 +kM\
D~D1
Dateadd(wk,datediff(wk,0,getdate()),-1) yr5NRs
Dateadd(wk,datediff(wk,0,getdate()),6) 3!aEClRtq
就是表示本周时间段. 0C]4~F x~
下面的SQL的条件部分,就是查询时间段在本周范围内的: i-b1d'?Rb
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 0 sZwdO
而在存储过程中 NEMEY7De2
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) y`rL=N#
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) WHP;Neb6