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。 U(3(ZqP
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一、基础 o4'v> b
1、说明:创建数据库 |F~88j{VN
CREATE DATABASE database-name :1BM=_WwI
2、说明:删除数据库 e-!?[Ujv*%
drop database dbname QE6El'S
3、说明:备份sql server 4Bo<4 4-,
--- 创建 备份数据的 device z.59]\;U>
USE master <rMv0y+r
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' U 1F-~{r
--- 开始 备份 !Ud:?U
BACKUP DATABASE pubs TO testBack }MjQP R
4、说明:创建新表 (.
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) u7(];
根据已有的表创建新表: zg7G^!PU
A:create table tab_new like tab_old (使用旧表创建新表) aL 8Gnqf2
B:create table tab_new as select col1,col2... from tab_old definition only 8vO;IK]9b^
5、说明:删除新表 Q(blW
drop table tabname E4i@|jE~)
6、说明:增加一个列 B{=009.
Alter table tabname add column col type Rd vn)K
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。 1(#RN9
7、说明:添加主键: Alter table tabname add primary key(col) QD}1?)}
说明:删除主键: Alter table tabname drop primary key(col) %2zas(b9j
8、说明:创建索引:create [unique] index idxname on tabname(col....) Y^X:vI
删除索引:drop index idxname - &NQ\W
注:索引是不可更改的,想更改必须删除重新建。 F1\`l{B,\
9、说明:创建视图:create view viewname as select statement km}MqBQl
删除视图:drop view viewname E{I)]h
10、说明:几个简单的基本的sql语句 m1i4 ,
选择:select * from table1 where 范围 ~r PYJ
插入:insert into table1(field1,field2) values(value1,value2) k~R{Y~W!!
删除:delete from table1 where 范围 |""=)-5N
更新:update table1 set field1=value1 where 范围 '6+Edu~Ho)
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! #_{0Ndp2
排序:select * from table1 order by field1,field2 [desc] S$\.4*_H\
总数:select count as totalcount from table1
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求和:select sum(field1) as sumvalue from table1 PE|PwqX
平均:select avg(field1) as avgvalue from table1 AzxL%,_
最大:select max(field1) as maxvalue from table1 P6:;Y5e0
最小:select min(field1) as minvalue from table1 CJm.K
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11、说明:几个高级查询运算词 |G)Y8 #D
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A: UNION 运算符 =?HzNA$yh
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。 ka!Bmv)
B: EXCEPT 运算符 ENO? ;
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。 Z@}sCZ=#A
C: INTERSECT 运算符 Ut]2` 8-
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。 #UBB
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注:使用运算词的几个查询结果行必须是一致的。 (*MNox?w
12、说明:使用外连接 [gpOuTW
A、left outer join: O@nqHZ
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。 {K<uM'ww>
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 L+8=P<]
B:right outer join: 8^8>qSD1
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。 xrfPZBLy
C:full outer join: r }ZLf
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。 kJI3`gS+
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二、提升 P87ld._
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) TH<fbd
法一:select * into b from a where 1<>1 K2*1T+?X
法二:select top 0 * into b from a /%62X{=>;
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) CdDH1[J
insert into b(a, b, c) select d,e,f from b; 3\7'm]
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) "!xvpsy
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 O;UiYrXU
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. PP!l
4、说明:子查询(表名1:a 表名2:b) a_Z.J3
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) f9vcf# 2
5、说明:显示文章、提交人和最后回复时间 9!5b2!JL
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b qo61O\qm
6、说明:外连接查询(表名1:a 表名2:b) T}V7SD.
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c TG4\%S$w
7、说明:在线视图查询(表名1:a ) CKx\V+\O
select * from (SELECT a,b,c FROM a) T where t.a > 1; Sc% aJ1
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 tDEXm^B2Sv
select * from table1 where time between time1 and time2 iP2U]d~M
select a,b,c, from table1 where a not between 数值1 and 数值2 :/>7$)+
9、说明:in 的使用方法 ^Vl^,@
select * from table1 where a [not] in ('值1','值2','值4','值6') ;>inT7?3|
10、说明:两张关联表,删除主表中已经在副表中没有的信息 iPA@<D%
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) -"2 <h:#
11、说明:四表联查问题: 2~#ZO?jE6
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 ..... /uC+.B9k
12、说明:日程安排提前五分钟提醒 2ZU@>W
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 GA'*58
13、说明:一条sql 语句搞定数据库分页 CbnR<W-j
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 )EhTM-1
14、说明:前10条记录 +<'uw
select top 10 * form table1 where 范围 r$b:1 C~
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.) +#|'|}j
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 1i5 vW- '4
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 Hi9 G^Q
(select a from tableA ) except (select a from tableB) except (select a from tableC) #cw!
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17、说明:随机取出10条数据 #B}BI8o (
select top 10 * from tablename order by newid() o@qN#Mg?>}
18、说明:随机选择记录 :GN)7|:
select newid() d[~au=b
19、说明:删除重复记录 1.hOE>A%
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) C\;;9
20、说明:列出数据库里所有的表名 $=\oJ-(!@S
select name from sysobjects where type='U' @)aXNQY
21、说明:列出表里的所有的 vG'vgUo
select name from syscolumns where id=object_id('TableName') NTv#{7q
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 / e~
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type *T.={>HE8
显示结果: h#(.(d
type vender pcs 5pNvzw
电脑 A 1 !mw{T D
电脑 A 1 D6C-x
光盘 B 2 J,dG4.ht
光盘 A 2 EG Q1li'B
手机 B 3 !nP8ysB
手机 C 3 b&hF')_UOz
23、说明:初始化表table1 [8V(N2
TRUNCATE TABLE table1 '^P*F9
24、说明:选择从10到15的记录 ?RrC~7~
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Z'*G'/*
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三、技巧 30gZ_8C>}
1、1=1,1=2的使用,在SQL语句组合时用的较多 1s^$oi}
"where 1=1" 是表示选择全部 "where 1=2"全部不选, U 8qKD
如: FM@W>+
if @strWhere !='' Ep v3/`I
begin xX/Qoq (}i
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere W#JVU GYD
end hc@;}a\Y
else nU">> 1!U
begin ek+8hnkh
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' `#IT24!
end ^{6UAT~!R
我们可以直接写成 _If@#WnoyA
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere nKZRq&~^E
2、收缩数据库 %r}KvJgd
--重建索引 {~B4F}ES
DBCC REINDEX ( .6tz
DBCC INDEXDEFRAG x""Mxn]gD
--收缩数据和日志 $[^ KCNB
DBCC SHRINKDB Eb{4.17b
DBCC SHRINKFILE K{[Fa,]'
3、压缩数据库 ^5zS2nm
dbcc shrinkdatabase(dbname) OU
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4、转移数据库给新用户以已存在用户权限 |L~gNC
exec sp_change_users_login 'update_one','newname','oldname' .q;RNCUt
go ve_4@J)
5、检查备份集 ud~VQXZo
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' OM"T)4z
6、修复数据库 ,y{fqa4
ALTER DATABASE [dvbbs] SET SINGLE_USER @_tA"E
GO A$Jn3Xd~!
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 94>7-d
GO 5xn0U5U
ALTER DATABASE [dvbbs] SET MULTI_USER ?eg@
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GO Lu$:,^ C
7、日志清除 jWb\"0)
SET NOCOUNT ON daokiU+l2
DECLARE @LogicalFileName sysname, a1Y _0
@MaxMinutes INT, f@V{}&ZWp
@NewSize INT .q& ]wu
USE tablename -- 要操作的数据库名 SUQ}^gn]
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 EXM/>PG
@MaxMinutes = 10, -- Limit on time allowed to wrap log. -:1Gr8
@NewSize = 1 -- 你想设定的日志文件的大小(M) ]MH
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-- Setup / initialize #$
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DECLARE @OriginalSize int 0a;FX0S&
SELECT @OriginalSize = size l#(g&x6J
FROM sysfiles tGy%n[ \
WHERE name = @LogicalFileName Yv`1ySR
SELECT 'Original Size of ' + db_name() + ' LOG is ' + qm&53
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + AXv3jH,HF
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Z~R/p;@
FROM sysfiles 1PjX:]:
WHERE name = @LogicalFileName @eD~FNf-]
CREATE TABLE DummyTrans C@:N5},]
(DummyColumn char (8000) not null) V:$1o
DECLARE @Counter INT, kO\&mL&
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@StartTime DATETIME, LAjw!QB
@TruncLog VARCHAR(255) tYxlM!
SELECT @StartTime = GETDATE(), B 0fo[Ev
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' K Qy\l+\gM
DBCC SHRINKFILE (@LogicalFileName, @NewSize) PYRwcJ$b\d
EXEC (@TruncLog) dodz|5o%
-- Wrap the log if necessary. g&20F`.N*>
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 5;%xqdD
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ,}xC) >
AND (@OriginalSize * 8 /1024) > @NewSize OaVL NA^{
BEGIN -- Outer loop. ZkG##Jp\>
SELECT @Counter = 0 L?5t<`#lw
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Kof-;T
BEGIN -- update 91'^--N
INSERT DummyTrans VALUES ('Fill Log') =>TtX@ Q{
DELETE DummyTrans ]$X=~>w
SELECT @Counter = @Counter + 1 :=KGQ3V~eK
END A7}|VV
EXEC (@TruncLog) (>% Vj
END lIT2 AFX+
SELECT 'Final Size of ' + db_name() + ' LOG is ' + }LVE^6zyk
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + nFOG=>c}
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' R}YryzV5
FROM sysfiles "alO"x8t
WHERE name = @LogicalFileName 5_T>HHR6
DROP TABLE DummyTrans ?9M+fi
SET NOCOUNT OFF Hqy>!1!
8、说明:更改某个表 nK;
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exec sp_changeobjectowner 'tablename','dbo' +2enz!z#k
9、存储更改全部表 w4/)r-Z4I
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ZI*A0_;L
@OldOwner as NVARCHAR(128), lY8Qy2k|
@NewOwner as NVARCHAR(128) 8U$UI
AS {
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DECLARE @Name as NVARCHAR(128) RB@gSHOc?
DECLARE @Owner as NVARCHAR(128) zm.sX~j
DECLARE @OwnerName as NVARCHAR(128) S`-IQ,*}
DECLARE curObject CURSOR FOR Icb;Yzt
select 'Name' = name, eJdQ7g[>
'Owner' = user_name(uid) ,l"2MXD
from sysobjects BuO J0$
where user_name(uid)=@OldOwner %}MM+1eu
order by name eesLTyD2_
OPEN curObject )W#g@V)>
FETCH NEXT FROM curObject INTO @Name, @Owner z{_Vn(Kg
WHILE(@@FETCH_STATUS=0) p 8rAtz>=J
BEGIN FX%E7H
if @Owner=@OldOwner vK/Z9wR*05
begin vCr$miZ
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 2(x KE_|
exec sp_changeobjectowner @OwnerName, @NewOwner 8hV:bz"
end 'KrkCA
-- select @name,@NewOwner,@OldOwner e;\c=J,eE
FETCH NEXT FROM curObject INTO @Name, @Owner NV ~i4R*#
END B*Xh$R
close curObject k82LCV+6
deallocate curObject !I$RE?7eY
GO Jx7^|A
10、SQL SERVER中直接循环写入数据 yQ2[[[@k@
declare @i int 8`<GplO
set @i=1 =i<(hgD
while @i<30 9a,CiH%@
begin l0)6[yXK
insert into test (userid) values(@i) $RO=r90o
set @i=@i+1 Tl-B[CT
end >@W#@W*I@
小记存储过程中经常用到的本周,本月,本年函数 81C?U5
Dateadd(wk,datediff(wk,0,getdate()),-1) U{m:{'np(H
Dateadd(wk,datediff(wk,0,getdate()),6) /pEkig7M
Dateadd(mm,datediff(mm,0,getdate()),0) $x0F(|wxt
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 4(]('[M
Dateadd(yy,datediff(yy,0,getdate()),0) =25"qJr
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) )HcC\[
上面的SQL代码只是一个时间段 p `Z7VG
Dateadd(wk,datediff(wk,0,getdate()),-1) 3Q;l*xu
Dateadd(wk,datediff(wk,0,getdate()),6) s4*,ocyBP
就是表示本周时间段. %UhF=C
下面的SQL的条件部分,就是查询时间段在本周范围内的: ponvi42u
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) jiDYPYx;I
而在存储过程中 |M&/(0
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 3._fbAN%e
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Z]CH8GS~<