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。 m,E$KHt (
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一、基础 pD732L@q
1、说明:创建数据库 9RaO[j`
CREATE DATABASE database-name (G>[A}-
2、说明:删除数据库 ;[sW\Ou
drop database dbname { :tO
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3、说明:备份sql server J/?Nf2L4
--- 创建 备份数据的 device // o.+?S
USE master LSJ?;Zg(=z
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ;"wCBuXcu
--- 开始 备份 i/ilG3m>
BACKUP DATABASE pubs TO testBack _6ZjF>f
4、说明:创建新表 ~.m<`~u
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) F3qK6Ah.
根据已有的表创建新表: /9w>:i81
A:create table tab_new like tab_old (使用旧表创建新表) !LI<%P)
B:create table tab_new as select col1,col2... from tab_old definition only ~9dpB>+
5、说明:删除新表 RwWg:4
drop table tabname "#j}F u_!
6、说明:增加一个列
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Alter table tabname add column col type DYD<?._I
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。 .w9LJ
7、说明:添加主键: Alter table tabname add primary key(col) BPba3G9H
说明:删除主键: Alter table tabname drop primary key(col) Cl}nPUoL
8、说明:创建索引:create [unique] index idxname on tabname(col....) Nz,yd%ua
删除索引:drop index idxname *glZb;_
注:索引是不可更改的,想更改必须删除重新建。 +T+@g8S
9、说明:创建视图:create view viewname as select statement h4?x_"V"
删除视图:drop view viewname FRBu8WW0L
10、说明:几个简单的基本的sql语句 9Yx(u2PQ
选择:select * from table1 where 范围 'x!\pE-
插入:insert into table1(field1,field2) values(value1,value2) afEa@et'
删除:delete from table1 where 范围 V)`2Kw
更新:update table1 set field1=value1 where 范围 IY`p7 )#i
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! =?fz-HB
排序:select * from table1 order by field1,field2 [desc] $<^t][{
总数:select count as totalcount from table1 Dm>"c;2
求和:select sum(field1) as sumvalue from table1 IU%|K~_n
平均:select avg(field1) as avgvalue from table1 %z><)7
最大:select max(field1) as maxvalue from table1 yGZsNd {a&
最小:select min(field1) as minvalue from table1 \c=I!<9
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11、说明:几个高级查询运算词 X
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A: UNION 运算符 Bh>L"'.2
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。 d8j1L/e
B: EXCEPT 运算符 P#,u9EIJ
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。 G 6sK3K
C: INTERSECT 运算符 f!Q\M1t)
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。 T~TP
注:使用运算词的几个查询结果行必须是一致的。 ggr
12、说明:使用外连接 \hB BG8=&
A、left outer join: <uH8Fivb
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。 @;Ttdwg#J
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 6o3
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B:right outer join: mPV<a&U
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。 kSQ8kU_w+
C:full outer join: '|C3t!H`
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。 ly[LF1t
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二、提升 c7Z4u|G
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Zp_(vOc
法一:select * into b from a where 1<>1 d2
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法二:select top 0 * into b from a RU )35oEV|
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Y?VbgOM)
insert into b(a, b, c) select d,e,f from b; {f!/:bM
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) ?9b9{c'an
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 +]db-
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. *2'8d8>R%]
4、说明:子查询(表名1:a 表名2:b) K"}fD;3
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) _]Hna <Ly
5、说明:显示文章、提交人和最后回复时间 g*|j+<:7
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b %\As
6、说明:外连接查询(表名1:a 表名2:b) \{,TpK.
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c @=Kq99=\U
7、说明:在线视图查询(表名1:a ) }{aGh I~<
select * from (SELECT a,b,c FROM a) T where t.a > 1; R$awg SE
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 IP~!E_e}\
select * from table1 where time between time1 and time2 nR!e(
select a,b,c, from table1 where a not between 数值1 and 数值2 (
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9、说明:in 的使用方法 FqKJids-
select * from table1 where a [not] in ('值1','值2','值4','值6') yC,/R371k
10、说明:两张关联表,删除主表中已经在副表中没有的信息 INZVe(z
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Q M,!-~t
11、说明:四表联查问题: |.IH4
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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 ..... I$Nh|eM
12、说明:日程安排提前五分钟提醒 {Z.6\G&q
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 f0Q6sV ZHa
13、说明:一条sql 语句搞定数据库分页 "(koR Q
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 (}"D x3K
14、说明:前10条记录 g8),$:Uw
select top 10 * form table1 where 范围 g(DD8;]w<
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.) GN.Oa$
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ZO}Og&%
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 l{3B}_,
(select a from tableA ) except (select a from tableB) except (select a from tableC) 9N]Xa
17、说明:随机取出10条数据 e5h*GKF
select top 10 * from tablename order by newid() >%JPgr/
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18、说明:随机选择记录 'nJF:+30ZH
select newid() fGgt[f[
19、说明:删除重复记录 lG*Rw-?a
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) )oEVafNsT
20、说明:列出数据库里所有的表名 &{iC:zp
select name from sysobjects where type='U' ]AP1+
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21、说明:列出表里的所有的 ><%585
select name from syscolumns where id=object_id('TableName') ~m%[d.
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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。 ffCDO\i({
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 C2LPLquD+
显示结果: |J`EM7qMK
type vender pcs h@)U,&
电脑 A 1 WxdQ^#AE
电脑 A 1 BEZ~<E&0H
光盘 B 2 7AG|'s['=
光盘 A 2 ;%|im?
手机 B 3 NgNGq\!
手机 C 3 95 ;{ms[
23、说明:初始化表table1 ~ KK9aV{
TRUNCATE TABLE table1 UuG%5 ZC
24、说明:选择从10到15的记录 F[qXIL)
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc t2&kGf"
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三、技巧 pjl%Jm
1、1=1,1=2的使用,在SQL语句组合时用的较多 r)(5,*v
"where 1=1" 是表示选择全部 "where 1=2"全部不选, P-m_],
如: w+o5iPLX
if @strWhere !='' *0WVrM06?
begin {f*Y}/@
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere \BOoY# !a
end ,|%KlHo^
else 3CUQQ_
begin I-v}
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 3F9V,zWtTi
end ~W'DEpq_
我们可以直接写成 P\7DA4]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 5f0M{J,KC
2、收缩数据库 pP\Cwo #,
--重建索引 !3Dq)ebBz
DBCC REINDEX 5zuwqOD*
DBCC INDEXDEFRAG sYTz6-
--收缩数据和日志 lR(9;3
DBCC SHRINKDB %wD#[<BGn>
DBCC SHRINKFILE yCX5
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3、压缩数据库
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dbcc shrinkdatabase(dbname) 'Kelq$dn#
4、转移数据库给新用户以已存在用户权限 68%aDs
exec sp_change_users_login 'update_one','newname','oldname' *4O=4F)x
go dQX-s=XJ
5、检查备份集 D{9a'0J
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' egmUUuO
6、修复数据库
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ALTER DATABASE [dvbbs] SET SINGLE_USER u#05`i:Z
GO !_glZ*tL
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK .j6udiv5
GO 2j\_svw'
ALTER DATABASE [dvbbs] SET MULTI_USER [V}vd@*k
GO +)jUA]hJ/
7、日志清除 F)P:lvp<r
SET NOCOUNT ON QE]@xLz
DECLARE @LogicalFileName sysname, 6]4~]!
@MaxMinutes INT, iUKjCq02
@NewSize INT 5hs_k[q
USE tablename -- 要操作的数据库名 ]l7W5$26 @
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Po>6I0y
@MaxMinutes = 10, -- Limit on time allowed to wrap log. SA,~q&
@NewSize = 1 -- 你想设定的日志文件的大小(M) t@KTiJI
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-- Setup / initialize q|5WHB
DECLARE @OriginalSize int K5>3
SELECT @OriginalSize = size eAHY/Y!
FROM sysfiles 5!0iK9O
WHERE name = @LogicalFileName (6,:X
SELECT 'Original Size of ' + db_name() + ' LOG is ' + AvL /gt:
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + %$BRQ-O
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 7uBx
FROM sysfiles x;ik
WHERE name = @LogicalFileName K'OG-fn;
CREATE TABLE DummyTrans 'CBwE&AL
(DummyColumn char (8000) not null) "2e3 <:$
DECLARE @Counter INT, l;$F[/3a
@StartTime DATETIME, "$BkO[IS
@TruncLog VARCHAR(255) }gSoBu
SELECT @StartTime = GETDATE(), f/\!=sa:
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 8 Ku9;VEk
DBCC SHRINKFILE (@LogicalFileName, @NewSize) N'1I6e"
EXEC (@TruncLog) *0U#Z]t
-- Wrap the log if necessary. L F?/60
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired zD_5TGM=
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) hV3]1E21"
AND (@OriginalSize * 8 /1024) > @NewSize _/[qBe
BEGIN -- Outer loop. +|?a7qM
SELECT @Counter = 0 &BVUK"}P
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) e\)%<G5
BEGIN -- update u5CSx'h]
INSERT DummyTrans VALUES ('Fill Log') I0-1Hr
DELETE DummyTrans Kq7r+A
SELECT @Counter = @Counter + 1 L5hF-Ek!
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END NF$6yv9C
EXEC (@TruncLog) %Tp9GGt
END #rHMf%0
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ^Ks1[xc* `
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + @`.4"*@M
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 0+&WIs
FROM sysfiles
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WHERE name = @LogicalFileName UG vIH m
DROP TABLE DummyTrans R ENCk(
SET NOCOUNT OFF [gzaOP`f
8、说明:更改某个表 oKGH|iVEe
exec sp_changeobjectowner 'tablename','dbo' =i~
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9、存储更改全部表 @= <{_p
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch l,n_G/\
@OldOwner as NVARCHAR(128), d%EdvM|)
@NewOwner as NVARCHAR(128) DLwlA!z
AS piIZ*@'
DECLARE @Name as NVARCHAR(128) t/i*.>7
DECLARE @Owner as NVARCHAR(128) ?!ap@)9
DECLARE @OwnerName as NVARCHAR(128) Ust +g4
DECLARE curObject CURSOR FOR :GvC#2p
select 'Name' = name, SiNgV\('U
'Owner' = user_name(uid) &zn|),
from sysobjects h]zok}$
where user_name(uid)=@OldOwner .]9`eGVWj
order by name cGE{dWz
OPEN curObject R;"$ PHD
FETCH NEXT FROM curObject INTO @Name, @Owner s:<y\1Ay
WHILE(@@FETCH_STATUS=0) {[uhIJD3g6
BEGIN 2e6P?pX~2
if @Owner=@OldOwner (JU8F-/9
begin (4Db%Iw
set @OwnerName = @OldOwner + '.' + rtrim(@Name) za>%hZf\
exec sp_changeobjectowner @OwnerName, @NewOwner P, x"![6
end oy[s])Tg
-- select @name,@NewOwner,@OldOwner M:O*_>KF
FETCH NEXT FROM curObject INTO @Name, @Owner +5fB?0D;
END df{?E):
close curObject n%r>W^2j
deallocate curObject lG6&uMvo
GO
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10、SQL SERVER中直接循环写入数据 )~M@2;@L
declare @i int U& GPede
set @i=1 mmQC9nZ
while @i<30 tFcQ.1
begin ( w4XqVT
insert into test (userid) values(@i) d 6Y9D=O
set @i=@i+1 ['QhC( {
end $y;w@^
小记存储过程中经常用到的本周,本月,本年函数 kwi$%
Dateadd(wk,datediff(wk,0,getdate()),-1) /@"mQx~[q
Dateadd(wk,datediff(wk,0,getdate()),6) mR.j8pi
Dateadd(mm,datediff(mm,0,getdate()),0) @Z0. }}Y
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) n6[shXH
Dateadd(yy,datediff(yy,0,getdate()),0) +s}!+I8P
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) D[W`
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上面的SQL代码只是一个时间段 JKKp5~_~
Dateadd(wk,datediff(wk,0,getdate()),-1) \Vv)(/q {
Dateadd(wk,datediff(wk,0,getdate()),6) H:b"Vd"x9
就是表示本周时间段. '4{@F~fu
下面的SQL的条件部分,就是查询时间段在本周范围内的: ~vP_c(8f
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) f*@
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而在存储过程中 qX&+
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) .0nT*LF
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) `LH 9@Z{