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。 b
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一、基础 ?{[ISk)
1、说明:创建数据库 {}kE=L5
CREATE DATABASE database-name tPB r{
2、说明:删除数据库 _y*@Hj
drop database dbname Ri=:=oF(
3、说明:备份sql server 8yij=T*
--- 创建 备份数据的 device o@*eC L=
USE master OC34@YUj[
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' (KtuikJ32^
--- 开始 备份 _&)^a)Nu
BACKUP DATABASE pubs TO testBack NF8'O
4、说明:创建新表 ?~X*\
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) vik A
根据已有的表创建新表: ;rXkU9
A:create table tab_new like tab_old (使用旧表创建新表) }K':tX?
B:create table tab_new as select col1,col2... from tab_old definition only Q#w mS&$f
5、说明:删除新表 &YC Z
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drop table tabname *(wkgn
6、说明:增加一个列 > Dy<@e
Alter table tabname add column col type U l8G R
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 & mwQj<Z
7、说明:添加主键: Alter table tabname add primary key(col) d5Hp&tm
说明:删除主键: Alter table tabname drop primary key(col) aO8n\'bv
8、说明:创建索引:create [unique] index idxname on tabname(col....) 1Tl^mS~k
删除索引:drop index idxname PxfWO1S(
注:索引是不可更改的,想更改必须删除重新建。 VBnD:w"z
9、说明:创建视图:create view viewname as select statement Sggha~E2s
删除视图:drop view viewname KZrg4TEVi
10、说明:几个简单的基本的sql语句 &\tD$g~"
选择:select * from table1 where 范围 7[z^0?Pygf
插入:insert into table1(field1,field2) values(value1,value2) g~EN3~
删除:delete from table1 where 范围 7X
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更新:update table1 set field1=value1 where 范围 s8BfOl-
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! k{\wjaf)
排序:select * from table1 order by field1,field2 [desc] Q^13KWvuV
总数:select count as totalcount from table1 *Z}^T:3iw}
求和:select sum(field1) as sumvalue from table1 %87D(h!.I4
平均:select avg(field1) as avgvalue from table1 RN:VsopL
最大:select max(field1) as maxvalue from table1 "/H B#
最小:select min(field1) as minvalue from table1 )gF>nNE
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11、说明:几个高级查询运算词 )(b,v/:
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A: UNION 运算符 XBx&&
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。 -c%#Hd
B: EXCEPT 运算符 ,~8&0p
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。 WxPu{N
C: INTERSECT 运算符 *^[m?3"W
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。 @yV.Yx"p_
注:使用运算词的几个查询结果行必须是一致的。 gn82_
12、说明:使用外连接 <&w(%<;
A、left outer join: zXX=WH
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。 kXW5bR
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 CE,0@%6F*
B:right outer join: 78M%[7Cq<i
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。 .X1xpi%
C:full outer join: {ovt
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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。 b'AA*v,b
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二、提升 r?9D/|`
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) S<*h1}V3/
法一:select * into b from a where 1<>1 FYBW3y+AF&
法二:select top 0 * into b from a I{nrOb1G(
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) q,;8Ka )
insert into b(a, b, c) select d,e,f from b; !2=m
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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) ]?p 9)d=%<
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 MS5X#B
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Yt]Y(
4、说明:子查询(表名1:a 表名2:b) d.e_\]o<@
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) N[=c|frho
5、说明:显示文章、提交人和最后回复时间 K&"ZZFd_
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 0*J},#ba$
6、说明:外连接查询(表名1:a 表名2:b) cQzUR^oq,
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ] 6Y6q])Z
7、说明:在线视图查询(表名1:a ) x)+ q$FB
select * from (SELECT a,b,c FROM a) T where t.a > 1; " fXs!
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 Pk?M~{S
select * from table1 where time between time1 and time2 4 H9mKR
select a,b,c, from table1 where a not between 数值1 and 数值2 i<\WRzVT
9、说明:in 的使用方法 #'y4UN
select * from table1 where a [not] in ('值1','值2','值4','值6') DpbprT7_
10、说明:两张关联表,删除主表中已经在副表中没有的信息 _ASyGmO{
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) .n\j<Kq
11、说明:四表联查问题: 6uS;H]nd<
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 ..... ,vDSY N6
12、说明:日程安排提前五分钟提醒 z( !K8
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 O'rz
13、说明:一条sql 语句搞定数据库分页 '_q&~M{
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 TI5<'
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14、说明:前10条记录 k,,Bf-?
select top 10 * form table1 where 范围 Sdzl[K/}
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.) 0{^ 0>H0
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) qtR/K=^i
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 )U|0vr8:
(select a from tableA ) except (select a from tableB) except (select a from tableC) ~o8
17、说明:随机取出10条数据 `g}po%k
select top 10 * from tablename order by newid() @|2sF
18、说明:随机选择记录 '"m-kor
select newid() fK/|0@B8
19、说明:删除重复记录 >,6%Y3
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Zdfruzl&`
20、说明:列出数据库里所有的表名 ]Uj7f4)k
select name from sysobjects where type='U' aG&t gD{
21、说明:列出表里的所有的 b[U;P=;=
select name from syscolumns where id=object_id('TableName') 2F&VG|"
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。 9Zj9e
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 jp+s[rRc\{
显示结果: L#k`>Qn2
type vender pcs % <1&\5f<5
电脑 A 1 cj;k{Moc
电脑 A 1 <Z
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光盘 B 2 w#
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光盘 A 2 yedEI[_4
手机 B 3 Mp`!zwR
手机 C 3 [QDM_n
23、说明:初始化表table1 a{
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TRUNCATE TABLE table1 X..<U}e
24、说明:选择从10到15的记录 {>Yna"p
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc DCP
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三、技巧 ^k2g60]
1、1=1,1=2的使用,在SQL语句组合时用的较多 *{!E`),FX
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Y52TC@'
如: 5~FXy{ZIH
if @strWhere !='' /B!Ik:c}
begin ?s5/
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere .+A2\F.^
end o?|
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else GL-Pir
begin nN%Zed2O@6
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Pi5($cn
end sl_f+h0
我们可以直接写成 (DQ ]58&
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere yJGnN g
2、收缩数据库 jaL#
--重建索引 /k.?x] Ab
DBCC REINDEX ^&7gUH*v
DBCC INDEXDEFRAG '/F%
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--收缩数据和日志 2-dEie/{'
DBCC SHRINKDB ja&S^B^@
DBCC SHRINKFILE @(CJT-Ak
3、压缩数据库 E$C0\O!7
dbcc shrinkdatabase(dbname) m% %\k
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4、转移数据库给新用户以已存在用户权限 VmON}bb[zz
exec sp_change_users_login 'update_one','newname','oldname' MlV3qM@
go B=)tq.Q7
5、检查备份集 ih=O#f|
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 3H`r|R
6、修复数据库 gxc8O).5vY
ALTER DATABASE [dvbbs] SET SINGLE_USER m\f}?t
GO Ksf f]##H
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK rqTsKrLe
GO IFbN ]N0
ALTER DATABASE [dvbbs] SET MULTI_USER @MxB
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GO &PUn,9 Rm
7、日志清除 M*Ri1
SET NOCOUNT ON wBz5_ OFVw
DECLARE @LogicalFileName sysname, m't8\fo^w
@MaxMinutes INT, rm%MQmF
@NewSize INT 534DAhpD=.
USE tablename -- 要操作的数据库名 +[":W?j
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 7|DPevrk
@MaxMinutes = 10, -- Limit on time allowed to wrap log. [5-3PuT&9
@NewSize = 1 -- 你想设定的日志文件的大小(M) $T7(AohR
-- Setup / initialize H`OJN.
DECLARE @OriginalSize int (9KiIRN
SELECT @OriginalSize = size TJ>$ ~9&Sy
FROM sysfiles `Y,<[ Lnr
WHERE name = @LogicalFileName i#%!J:_=
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^WUG\@B
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + e"cvo(}g
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' '_l5Br73=
FROM sysfiles ~=t K17i
WHERE name = @LogicalFileName r*g<A2g%
CREATE TABLE DummyTrans /DX6Hkkj %
(DummyColumn char (8000) not null) "b[w%KYyl
DECLARE @Counter INT, F.iJz4ya_
@StartTime DATETIME, @DuSii#.S
@TruncLog VARCHAR(255) %I#[k4,N
SELECT @StartTime = GETDATE(), rnP *}
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' _ q^JjR
DBCC SHRINKFILE (@LogicalFileName, @NewSize) S\0?~l"}
EXEC (@TruncLog) :+Tvq,/"
-- Wrap the log if necessary.
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired \<%?=C'w~
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) JgMYy,q8t
AND (@OriginalSize * 8 /1024) > @NewSize P;K <P
BEGIN -- Outer loop. jg3T1ROL
SELECT @Counter = 0 .$zo_~ mR
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) &+" )~2
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BEGIN -- update H'?dsc
INSERT DummyTrans VALUES ('Fill Log') !Q=xIS
DELETE DummyTrans ^oDSU7j5,
SELECT @Counter = @Counter + 1 UF;iw
END zXGi
EXEC (@TruncLog) k3UKGP1
END zhVkn]z~*
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Qsg([K
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + wZb77
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' N*'d]P2P`J
FROM sysfiles Eb89B%L62G
WHERE name = @LogicalFileName HME`7 dw?
DROP TABLE DummyTrans )KKmV6>b
SET NOCOUNT OFF B`?5G\7L
8、说明:更改某个表 v4VP7h6uD)
exec sp_changeobjectowner 'tablename','dbo' Fjw+D1q.
9、存储更改全部表 Y(R .e7]
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch !h>aP4ofT
@OldOwner as NVARCHAR(128), sEx`9_oZ
@NewOwner as NVARCHAR(128) <nJ8%aY,
AS ]]50c
DECLARE @Name as NVARCHAR(128) '7UIzk|
DECLARE @Owner as NVARCHAR(128) XX'mM v
DECLARE @OwnerName as NVARCHAR(128) lx&;?QQ
DECLARE curObject CURSOR FOR \s_`ZEB
select 'Name' = name, G$E+qk
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'Owner' = user_name(uid) }5=tUfh)]'
from sysobjects li&&[=6A
where user_name(uid)=@OldOwner )BmO[AiOM
order by name ]SG(YrF
OPEN curObject 3?s1Yw>?
FETCH NEXT FROM curObject INTO @Name, @Owner %ql2 XAY
WHILE(@@FETCH_STATUS=0) d[y(u<Vl
BEGIN nZ/pi$7
if @Owner=@OldOwner H",q-.!
begin Mb'Tx
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ;fZ9:WB
exec sp_changeobjectowner @OwnerName, @NewOwner p~17cH4~-f
end JQH>{OB
-- select @name,@NewOwner,@OldOwner =4804N7
FETCH NEXT FROM curObject INTO @Name, @Owner et}%E9
END i7foZ\btFc
close curObject 2Z7r ZjXW
deallocate curObject T*qSk!
GO 66|$X,
10、SQL SERVER中直接循环写入数据 C]NL9Gq`
declare @i int |WsB0R
set @i=1 tQIa6c4|
while @i<30 h.)o4(bO
begin W5R /
insert into test (userid) values(@i) 4(TR'_X(
set @i=@i+1 rfYFS96
end &nfGRb
小记存储过程中经常用到的本周,本月,本年函数 L[O.]2
Dateadd(wk,datediff(wk,0,getdate()),-1) -HUlB|Q8r
Dateadd(wk,datediff(wk,0,getdate()),6) zA*I=3E(
Dateadd(mm,datediff(mm,0,getdate()),0) v_I)eac z
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) /s "Lsbe
Dateadd(yy,datediff(yy,0,getdate()),0) { !NXu
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 1hW"#>f7
上面的SQL代码只是一个时间段 M7\yEi"*
Dateadd(wk,datediff(wk,0,getdate()),-1) MT{ovDA].
Dateadd(wk,datediff(wk,0,getdate()),6) yR[htD`
就是表示本周时间段. d'2q~
下面的SQL的条件部分,就是查询时间段在本周范围内的: _!E)a
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) /Bp5^(s
而在存储过程中 ^e(*{K;8
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 5?XIp6%x
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) o>Q=V0?