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。 C/Dc1sj
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一、基础 B?r [|
1、说明:创建数据库 nzHsyL
CREATE DATABASE database-name rTjV/~
2、说明:删除数据库 G#;$;
drop database dbname ZO $}m?
3、说明:备份sql server t`X-jr)g
--- 创建 备份数据的 device lvz&7Z b
USE master +kKfx!
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' <t0o{}^P*
--- 开始 备份 ?gMxGH:B.&
BACKUP DATABASE pubs TO testBack v='h
4、说明:创建新表 4#m"t?6!
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) vxzOG?Xc:
根据已有的表创建新表: skn`Q>a
A:create table tab_new like tab_old (使用旧表创建新表) )5U&^tJ
B:create table tab_new as select col1,col2... from tab_old definition only T=w5FT
5、说明:删除新表 EV 8}C=
drop table tabname D-BWgK
6、说明:增加一个列 ^w XXx=Xf
Alter table tabname add column col type )Aky:kM$
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。 L{\au5-4
7、说明:添加主键: Alter table tabname add primary key(col) jnuovM!x~
说明:删除主键: Alter table tabname drop primary key(col) fN TPW]
8、说明:创建索引:create [unique] index idxname on tabname(col....) I2=?H<
删除索引:drop index idxname r9@Q="J_)
注:索引是不可更改的,想更改必须删除重新建。 GJY7vS^#
9、说明:创建视图:create view viewname as select statement ?B2 T'}~
删除视图:drop view viewname ^\uj&K6l
10、说明:几个简单的基本的sql语句 <tbsQ3
选择:select * from table1 where 范围 J!o[/`4ib
插入:insert into table1(field1,field2) values(value1,value2) L;0ZB=3n
删除:delete from table1 where 范围 'o2x7~C@
更新:update table1 set field1=value1 where 范围 DM%4V|F"
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! C{
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排序:select * from table1 order by field1,field2 [desc] ||&EmH
总数:select count as totalcount from table1 .h2K$(/
求和:select sum(field1) as sumvalue from table1 }Zwse%;
平均:select avg(field1) as avgvalue from table1 gNO<`9q
最大:select max(field1) as maxvalue from table1 E{*~>#+
最小:select min(field1) as minvalue from table1 3Q`F x
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11、说明:几个高级查询运算词 )IGE2k|
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A: UNION 运算符 '~ 3a(1@8
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。 /YWoDHL
B: EXCEPT 运算符 m?G}%u
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。 %QUV351H
C: INTERSECT 运算符 ) w.cCDL c
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。 50oNN+;=R
注:使用运算词的几个查询结果行必须是一致的。 0sq1SHI{
12、说明:使用外连接 Y B@\"|}
A、left outer join: =j 6amk-
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。 AAkdwo
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 +.Kmpw4
B:right outer join: +pJ;}+
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。 A\Q]o#U
C:full outer join: ti)foam
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。 Ep0L51Q
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二、提升 z]> 0A
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) o_p//S#q
法一:select * into b from a where 1<>1 '+NmHu:q
法二:select top 0 * into b from a pr.Vfb
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ^u#!Yo.!(
insert into b(a, b, c) select d,e,f from b; S=^yJ6xJ
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) n*%<!\gJ
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 !}^c.<38Q
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. JY#IeNL
4、说明:子查询(表名1:a 表名2:b) OC9_EP\"
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) _d&zHlc_
5、说明:显示文章、提交人和最后回复时间 O B8fFd
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Nhn5 iN1*
6、说明:外连接查询(表名1:a 表名2:b) FGBPhH% (8
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c :k075Zr/#D
7、说明:在线视图查询(表名1:a ) =M)>w4-
select * from (SELECT a,b,c FROM a) T where t.a > 1; Y:]~~-f\~
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 umYq56dw
select * from table1 where time between time1 and time2 Rk56H
select a,b,c, from table1 where a not between 数值1 and 数值2 ' eO4h^
9、说明:in 的使用方法 eb2~$ ,$
select * from table1 where a [not] in ('值1','值2','值4','值6') H^p?t=Y
10、说明:两张关联表,删除主表中已经在副表中没有的信息 IP$^)t[
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) _L(6F
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11、说明:四表联查问题: BV$lMLD{r
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 ..... KP[ax2!x
12、说明:日程安排提前五分钟提醒 oDTt+b
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 tS8*l2Y`
13、说明:一条sql 语句搞定数据库分页 |:`f#H
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 @P6K`'.0
14、说明:前10条记录 FD*`$.e3\
select top 10 * form table1 where 范围 bT*MJ7VVm
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.) NTuS(7m
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) aG8}R~wH&
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 $:s1x\ol
(select a from tableA ) except (select a from tableB) except (select a from tableC) K7Kd{9-2
17、说明:随机取出10条数据 Axhe9!Fm
select top 10 * from tablename order by newid() g4&zBn
18、说明:随机选择记录 kWc%u-_
select newid() aAF:nyV~~0
19、说明:删除重复记录 l.\Fr+*ej
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) kYl$V=
20、说明:列出数据库里所有的表名 m'XzZmI
select name from sysobjects where type='U' ,Ww)>O+
21、说明:列出表里的所有的 5Y#yz>B@ ]
select name from syscolumns where id=object_id('TableName') 69ia #
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。 v2G_p|+O
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 ^q_0(Vf
显示结果: N?U;G*G
type vender pcs `MlQPLH
电脑 A 1 a9mLPP
电脑 A 1 "'p:M,:
光盘 B 2 Kjc"K36{L
光盘 A 2 DGj:qd(
手机 B 3 fySzZ
手机 C 3 ~t n*y4uK
23、说明:初始化表table1 uDay||7^g
TRUNCATE TABLE table1 ~dC)EG
24、说明:选择从10到15的记录 c<wsWs 4V
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Mi,yg=V
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三、技巧 v*<hE>J0
1、1=1,1=2的使用,在SQL语句组合时用的较多 jxL}tS{j
"where 1=1" 是表示选择全部 "where 1=2"全部不选, |sMRIW,P
如: SGre[+m~m
if @strWhere !='' U8-#W(tRR
begin /jaTH_Q),:
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere )~v`dwKj;
end ;"-(QE?Mv
else .C$S
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begin wUW^
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' rS\j9@=Y4
end x5YW6R.<t
我们可以直接写成 0z #'=XWk
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere )."_i64
2、收缩数据库 t*m04* }
--重建索引 CeSr~Ikg|
DBCC REINDEX ynvU$}w ~'
DBCC INDEXDEFRAG Hgu$)yhlj
--收缩数据和日志 f
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DBCC SHRINKDB %B}Q .'
DBCC SHRINKFILE ~ P"@^cq
3、压缩数据库 6O
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dbcc shrinkdatabase(dbname) {mrTpw
4、转移数据库给新用户以已存在用户权限 >8D!K0?E
exec sp_change_users_login 'update_one','newname','oldname' L3GA]TIf
go E^rKS&P
5、检查备份集 }pdn-#
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' aY}:9qBice
6、修复数据库 )=;GQ*<8Zs
ALTER DATABASE [dvbbs] SET SINGLE_USER Wf/r@/q
GO f_Ma~'3
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK dKTyh:_{
GO 3p6QJuSB
ALTER DATABASE [dvbbs] SET MULTI_USER Oq@+/UWX
GO f(:+JH<P~
7、日志清除 u,AP$+Qk
SET NOCOUNT ON B(7oHj.i2
DECLARE @LogicalFileName sysname, "XfCLc1 T
@MaxMinutes INT, y$|%K3
@NewSize INT yhv(KI
USE tablename -- 要操作的数据库名 Q@?8-
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Ok2KTsVl
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 5.5<.")
@NewSize = 1 -- 你想设定的日志文件的大小(M) 0^$L{V
-- Setup / initialize c.dk4v%Y5
DECLARE @OriginalSize int :7UC=GKQk
SELECT @OriginalSize = size $s+/OgG4H
FROM sysfiles 45. -P
WHERE name = @LogicalFileName v_mk{
SELECT 'Original Size of ' + db_name() + ' LOG is ' +
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + {L~j;p_G&
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' +wc8rE6+W
FROM sysfiles 0gO_dyB
WHERE name = @LogicalFileName mivb}cKM
CREATE TABLE DummyTrans rV84?75(Y
(DummyColumn char (8000) not null) <}t~^E,
DECLARE @Counter INT, J9eOBom8e<
@StartTime DATETIME, iGB1f*K%x
@TruncLog VARCHAR(255) *;t\!XDgp
SELECT @StartTime = GETDATE(), 0`c|ZzY
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' VK*Dm:G0
DBCC SHRINKFILE (@LogicalFileName, @NewSize) waI?X2
EXEC (@TruncLog) [p3{d\=*?
-- Wrap the log if necessary. .a2b&}/.d
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired (
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) :B{Wf 2<z
AND (@OriginalSize * 8 /1024) > @NewSize 7]W6\Z
BEGIN -- Outer loop. (rqc_ZU5
SELECT @Counter = 0 %]7'2
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) `ppyCUX
BEGIN -- update 0t*e#,y
INSERT DummyTrans VALUES ('Fill Log') \c}_!.xj"
DELETE DummyTrans N8x[8Rp
SELECT @Counter = @Counter + 1 \ vn!SO7
END ypU-/}Cf,
EXEC (@TruncLog) dUN{@a\R0
END $B%wK`J
SELECT 'Final Size of ' + db_name() + ' LOG is ' + }Q$}LR@
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + /T_{k.
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' U\*]cw
FROM sysfiles SU,G0.
WHERE name = @LogicalFileName =LXjq~p
DROP TABLE DummyTrans Gyx4}pV
SET NOCOUNT OFF i>z_6Gax*[
8、说明:更改某个表 a+'k#m
exec sp_changeobjectowner 'tablename','dbo' n*A?>NV
9、存储更改全部表 37apOK4+
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch #($~e|
@OldOwner as NVARCHAR(128), r{>Q{$Q
@NewOwner as NVARCHAR(128) UE9RrfdN
AS W(pq_H'
DECLARE @Name as NVARCHAR(128) .~$!BWP
DECLARE @Owner as NVARCHAR(128) {p\ll
DECLARE @OwnerName as NVARCHAR(128) e"oTlB
DECLARE curObject CURSOR FOR /H4Z.|@
select 'Name' = name, /RVwhA+c
'Owner' = user_name(uid) lfvt9!SJ+/
from sysobjects :HW| mqKd
where user_name(uid)=@OldOwner Y5c,O>T5Y
order by name R
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OPEN curObject rn^cajO^
FETCH NEXT FROM curObject INTO @Name, @Owner )]}G8A
WHILE(@@FETCH_STATUS=0) D:] QBA)C
BEGIN FKZ'6KM&A
if @Owner=@OldOwner yPrF2@#XZ/
begin Sq&r
;
set @OwnerName = @OldOwner + '.' + rtrim(@Name) s&hJ[$i
exec sp_changeobjectowner @OwnerName, @NewOwner QC,fyw\
end x~Y{
{
-- select @name,@NewOwner,@OldOwner H;nEU@>"Z
FETCH NEXT FROM curObject INTO @Name, @Owner 'C4cS[1
END LBxmozT
close curObject Vv54;Js9
deallocate curObject @An}
GO 0=0,ix7?#
10、SQL SERVER中直接循环写入数据 \sMe2OL#z
declare @i int *\.8*6*$!
set @i=1 &(7=NAQsE
while @i<30 <Y]e
begin _aeIK
insert into test (userid) values(@i) 3CzF@t;5
set @i=@i+1 4#CHX^De
end "(r%`.l=I
小记存储过程中经常用到的本周,本月,本年函数 ;6eBfMhL
Dateadd(wk,datediff(wk,0,getdate()),-1) jme`Tyd
Dateadd(wk,datediff(wk,0,getdate()),6) 0~~yYo&
Dateadd(mm,datediff(mm,0,getdate()),0) \q($8<
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) {xAd>fGG+y
Dateadd(yy,datediff(yy,0,getdate()),0) %pIP#y[4
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ;FQNO:NP
上面的SQL代码只是一个时间段 V408uy-M
Dateadd(wk,datediff(wk,0,getdate()),-1) 6hMKAk
Dateadd(wk,datediff(wk,0,getdate()),6) Fc#Sn2p*
就是表示本周时间段. A XhP3B]
下面的SQL的条件部分,就是查询时间段在本周范围内的: @9eN\b%I^H
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) cYp/? \
而在存储过程中 zauDwV=
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 6P3h955c
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) I8a3: )