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。 _wq?Pa<)e
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一、基础 [xMa^A>p
1、说明:创建数据库 Cx7-I0!
CREATE DATABASE database-name r\Nfq(w
2、说明:删除数据库 Wq1>Bj$J8
drop database dbname X]0>0=^
3、说明:备份sql server (`tRJWbdz
--- 创建 备份数据的 device c3vb~l)
USE master 4-(kk0]`z
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' P6:C/B
--- 开始 备份 `Fy-"Uf
BACKUP DATABASE pubs TO testBack $]v}X},,
4、说明:创建新表 h@:K=ggK
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) %By Pwu:f
根据已有的表创建新表: }#XFa#
A:create table tab_new like tab_old (使用旧表创建新表) + ?1GscJ
B:create table tab_new as select col1,col2... from tab_old definition only TktH28tK
5、说明:删除新表 2QfN.<[-
drop table tabname 7},A.q
6、说明:增加一个列 Tg\bpLk0=
Alter table tabname add column col type FfoOJzf~o
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 V>Wk\'h
7、说明:添加主键: Alter table tabname add primary key(col) OmYVJt_
说明:删除主键: Alter table tabname drop primary key(col) %oZ:Awx
8、说明:创建索引:create [unique] index idxname on tabname(col....) zzqJeIS
删除索引:drop index idxname CD|[PkjW
注:索引是不可更改的,想更改必须删除重新建。 p9(y b
9、说明:创建视图:create view viewname as select statement w0pMH p'Y
删除视图:drop view viewname pfA6?tP`
10、说明:几个简单的基本的sql语句 }U_
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选择:select * from table1 where 范围 k+3qX'fd
插入:insert into table1(field1,field2) values(value1,value2) *XVwTW[a
删除:delete from table1 where 范围 o2 14V \
更新:update table1 set field1=value1 where 范围 bx@l6bpQ
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! e[S`Dm"i)'
排序:select * from table1 order by field1,field2 [desc] GD
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总数:select count as totalcount from table1 wp[Ug2;G
求和:select sum(field1) as sumvalue from table1 7e/+C{3v
平均:select avg(field1) as avgvalue from table1 1>!LK_
最大:select max(field1) as maxvalue from table1 ?$ r`T]>`2
最小:select min(field1) as minvalue from table1 I[\~pi,
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11、说明:几个高级查询运算词 !40>LpL[
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A: UNION 运算符 =bVPHrKNQ
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。 1J@Iekat
B: EXCEPT 运算符 :!ya&o
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。 c\bL_
C: INTERSECT 运算符 Xlo7enzY
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。 cs9^&N:w[
注:使用运算词的几个查询结果行必须是一致的。 eRauyL"Q+
12、说明:使用外连接 3r\8v`^>
A、left outer join: vdQoJWuB
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。 *6uccx7{
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 i;[y!U
B:right outer join: En5oi
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。 K%(y<%Xp
C:full outer join: ==[,;g
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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。 !<bwg
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二、提升 #;!&8iH
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) K%^n.
法一:select * into b from a where 1<>1 8HF^^Cva
法二:select top 0 * into b from a )P$(]{
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用)
B.z$0=b
insert into b(a, b, c) select d,e,f from b; .
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3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) t6+m` Kq
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 0mw1CUx9K
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where..
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4、说明:子查询(表名1:a 表名2:b) 4s\spvJ
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) |<%!9Z
5、说明:显示文章、提交人和最后回复时间 FLZ9pb[T
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b MvVpp;bd
6、说明:外连接查询(表名1:a 表名2:b) (8 nv&|
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ,d
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7、说明:在线视图查询(表名1:a ) :<%bAn
select * from (SELECT a,b,c FROM a) T where t.a > 1; Iv`IJQH>
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 I[Ra0Q>([k
select * from table1 where time between time1 and time2 *Cy54Z#
select a,b,c, from table1 where a not between 数值1 and 数值2 S0$^|/Sr
9、说明:in 的使用方法 6&3,fSP
select * from table1 where a [not] in ('值1','值2','值4','值6') >J"IN I
10、说明:两张关联表,删除主表中已经在副表中没有的信息 oy+|:[v:Fk
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) -[>de!
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11、说明:四表联查问题: jU,Xlgz(A
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 ..... 8$00\><r
12、说明:日程安排提前五分钟提醒 [B0BHJ~
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 5>532X(0
13、说明:一条sql 语句搞定数据库分页 g40Hj Y
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 *MF9_V)8V
14、说明:前10条记录 vSzpx
select top 10 * form table1 where 范围 ?H{[u rLn
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) ZsGvv]P
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) "W<Y1$Y=Y
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 MDMd$]CW
(select a from tableA ) except (select a from tableB) except (select a from tableC) K+g[E<x\=
17、说明:随机取出10条数据 nD
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select top 10 * from tablename order by newid() 0zt]DCdY
18、说明:随机选择记录 A^U84kV=
select newid() ^$c#L1
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19、说明:删除重复记录 9u=A:n\
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) $ {yct
20、说明:列出数据库里所有的表名 ~o}:!y
select name from sysobjects where type='U' bQ<qdGa
21、说明:列出表里的所有的 sqkWQ`Ur
select name from syscolumns where id=object_id('TableName') \i.]-k
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。 bzN[*X|
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 V&mkS
显示结果: ^'UM@dd?!
type vender pcs Met?G0[
电脑 A 1 Pwh}hG1sa
电脑 A 1 ]xC56se
光盘 B 2 iO L$| Z(
光盘 A 2 x6ghO-s
手机 B 3 EOPx4+o
手机 C 3 U)}]Z@I-
23、说明:初始化表table1 -FeXG#{)
TRUNCATE TABLE table1 D%SOX N
24、说明:选择从10到15的记录 U%3N=M
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc wMa8HeBE\
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三、技巧 mc{z
1、1=1,1=2的使用,在SQL语句组合时用的较多 *d._H1zT
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ?kjQ_K
如: 8ud12^s$
if @strWhere !='' g*k)ws
begin ZmK=8iN9J
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere |Xt G9A>
end z} fpV T
else n 0!8)Sth
begin {C |R@S
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' c*KE3:
end EJ:O 1
我们可以直接写成 $6"sR I6u
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere \gA!)q.;
2、收缩数据库 ;i@S}LwL
--重建索引 zB.cOMx
DBCC REINDEX SYJO3cY
DBCC INDEXDEFRAG |q`NJ
--收缩数据和日志 >$q
DBCC SHRINKDB '-wmY?ZFxy
DBCC SHRINKFILE H'AN osv
3、压缩数据库 @9/I^Zk
dbcc shrinkdatabase(dbname) Ak[X`e T
4、转移数据库给新用户以已存在用户权限 \ `Hp/D1
exec sp_change_users_login 'update_one','newname','oldname' v9(5HY
go ^O|fw?,
5、检查备份集 ~${~To8$CW
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' oR#W@OK@is
6、修复数据库 o.Kn DY
ALTER DATABASE [dvbbs] SET SINGLE_USER !h?HfpYv
GO vF\>;pcT
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK
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GO u(vZOf]jL
ALTER DATABASE [dvbbs] SET MULTI_USER FJ_JaIby
GO cSL6V2F
7、日志清除 "ESc^28
SET NOCOUNT ON 6Bq_<3P_
DECLARE @LogicalFileName sysname, KL \>-
@MaxMinutes INT, t6Iy5)=zY
@NewSize INT \,S|>CPQ
USE tablename -- 要操作的数据库名 h@RpS8!Bi
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 kf@JEcKV
@MaxMinutes = 10, -- Limit on time allowed to wrap log. il^;2`]&
@NewSize = 1 -- 你想设定的日志文件的大小(M) b<FE
-- Setup / initialize 4,y7a=qf3
DECLARE @OriginalSize int suE K;Bk9
SELECT @OriginalSize = size ,Zmjw@w
FROM sysfiles h$5[04.Q
WHERE name = @LogicalFileName |z)s9B;:#i
SELECT 'Original Size of ' + db_name() + ' LOG is ' + )rEl{a
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + xPZ>vCg
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' YR'F]FI
FROM sysfiles |_?e.}K
WHERE name = @LogicalFileName
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CREATE TABLE DummyTrans L:HvrB~
(DummyColumn char (8000) not null) a0NiVF-m%
DECLARE @Counter INT, dWz?`B{'
@StartTime DATETIME, O9daeIF0#
@TruncLog VARCHAR(255) 3ijPm<wn
SELECT @StartTime = GETDATE(), ?R]`M_^&u!
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' n])#<0
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 6Vnq|;W3Zv
EXEC (@TruncLog) *2Pr1U
-- Wrap the log if necessary. biHacm
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired z&;8pZr
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ,X4b~)
AND (@OriginalSize * 8 /1024) > @NewSize \3hA_{ w
BEGIN -- Outer loop. !(lcUdBd
SELECT @Counter = 0 tp`1S+'~j
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) i"&FW&W
BEGIN -- update VcKB:(:[
INSERT DummyTrans VALUES ('Fill Log') F85_Lz4
DELETE DummyTrans o2
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SELECT @Counter = @Counter + 1 ~N!HxQ
END (;#c[eKy
EXEC (@TruncLog) m*m),mZ"
END )-
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + #gbB// <
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + G _cJI
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ^;EhKG
FROM sysfiles ,D{7=mDVm
WHERE name = @LogicalFileName gGMfy]]R
DROP TABLE DummyTrans 2 GRI<M
SET NOCOUNT OFF J+/}m}bx
8、说明:更改某个表 i}vJI}S.$
exec sp_changeobjectowner 'tablename','dbo' #,tT`{u1q
9、存储更改全部表 FJeh=\
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch \D|IN'!D
@OldOwner as NVARCHAR(128), BAQ-1kSz
@NewOwner as NVARCHAR(128) %jHm9{|X
AS `n$Ak5f
DECLARE @Name as NVARCHAR(128) AYnPxiW|
DECLARE @Owner as NVARCHAR(128) :7K
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DECLARE @OwnerName as NVARCHAR(128) ) lUS' I
DECLARE curObject CURSOR FOR 0j@mzd2
select 'Name' = name, &Ym):pc
'Owner' = user_name(uid) iTHwH{!
from sysobjects 9w-\K]
where user_name(uid)=@OldOwner [1rQ'FBB^1
order by name iaL@- dg
OPEN curObject |<Ls;:5.
FETCH NEXT FROM curObject INTO @Name, @Owner @6UtnX'd
WHILE(@@FETCH_STATUS=0) c~hH
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BEGIN L"ho|v9:
if @Owner=@OldOwner t9`{^<LH
begin pyhXET
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) 2W+~{3[#
exec sp_changeobjectowner @OwnerName, @NewOwner es7;eH*O9
end W_B=}lP@x
-- select @name,@NewOwner,@OldOwner 5e7Y M@ng
FETCH NEXT FROM curObject INTO @Name, @Owner 0%bCP/
END bqbG+g
close curObject ^BF}wQb:j
deallocate curObject 1h@qcom9K_
GO u[)X="-e#
10、SQL SERVER中直接循环写入数据 =7V4{|ESfy
declare @i int ^
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set @i=1 #}#m\=0
while @i<30 O?OAXPK2
begin u
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insert into test (userid) values(@i) L62'Amml
set @i=@i+1 Aits<0
end kQ>2W5o-d-
小记存储过程中经常用到的本周,本月,本年函数
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Dateadd(wk,datediff(wk,0,getdate()),-1) QYbB\Y
Dateadd(wk,datediff(wk,0,getdate()),6) :[<Y#EX.
Dateadd(mm,datediff(mm,0,getdate()),0) qe.QF."y
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) PMP{|yEx"
Dateadd(yy,datediff(yy,0,getdate()),0) 4<[?qd3v=
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) i\CA6I
上面的SQL代码只是一个时间段 i~Tt\UA>
Dateadd(wk,datediff(wk,0,getdate()),-1) Onx6Fy]L
Dateadd(wk,datediff(wk,0,getdate()),6) [#GBn0BG)
就是表示本周时间段. #ksDU
下面的SQL的条件部分,就是查询时间段在本周范围内的: nWsRauY
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) e]1=&:eX#d
而在存储过程中
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) *fm?"0M5
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 437Wy+Q|e