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。 K$$%j "s
)_l(WF.
K=P LOC5
一、基础 Ml_!)b
1、说明:创建数据库 "x3!F&
CREATE DATABASE database-name ?J"Y4,{
2、说明:删除数据库 `K2vG`c
drop database dbname fKs3H?|
3、说明:备份sql server CZCVC (/u
--- 创建 备份数据的 device 2\Yv;J+;
USE master | fn%!d`2
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' U71A#OD^U
--- 开始 备份 $K1)2WG
BACKUP DATABASE pubs TO testBack Vl:M6d1
4、说明:创建新表 (g tOYEqx
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) MR* %lZpB
根据已有的表创建新表: (Q|Y*yI
A:create table tab_new like tab_old (使用旧表创建新表) (B].ppBii
B:create table tab_new as select col1,col2... from tab_old definition only hLyV'*}
5、说明:删除新表 $bk_%R}s
drop table tabname %1i *Y*wg
6、说明:增加一个列 .n}k,da@(
Alter table tabname add column col type I=8MLv
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 "N=q>jaX
7、说明:添加主键: Alter table tabname add primary key(col) tqU8>d0^
说明:删除主键: Alter table tabname drop primary key(col) z)*\njYe
8、说明:创建索引:create [unique] index idxname on tabname(col....) 1| xKb(_l
删除索引:drop index idxname OJLyqncw
注:索引是不可更改的,想更改必须删除重新建。 A+hT2Ew@t}
9、说明:创建视图:create view viewname as select statement &([Gc+"5E.
删除视图:drop view viewname wY7+E/
10、说明:几个简单的基本的sql语句 3cFvS[JG
选择:select * from table1 where 范围 DEenvS`,P
插入:insert into table1(field1,field2) values(value1,value2) >LFj@YW_)
删除:delete from table1 where 范围 Nw3IDy~T
更新:update table1 set field1=value1 where 范围 k%LsjN.S
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! NB&zBJ#
排序:select * from table1 order by field1,field2 [desc] qh wl
总数:select count as totalcount from table1 T"Nnl(cO_
求和:select sum(field1) as sumvalue from table1 xQzXl
平均:select avg(field1) as avgvalue from table1 .zdmUS:
最大:select max(field1) as maxvalue from table1 wV{VV?h}
最小:select min(field1) as minvalue from table1 Wp=&nh
&$pA,Gjin\
i]zTY\gw8M
uU8L 93
11、说明:几个高级查询运算词 ,j[1!*Z_[
`$r?^|T
,Q8h#0z r
A: UNION 运算符 M3q7{w*bM
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 fR lJ`\ t
B: EXCEPT 运算符 i,$n4
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。 /oU$TaB>(
C: INTERSECT 运算符 *zDL5
9
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 JjQTD-^
注:使用运算词的几个查询结果行必须是一致的。 K`cy97
12、说明:使用外连接 zS}!87r)
A、left outer join: @<p9O0
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 3T@`VFbE
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c <kWNx.eci
B:right outer join: R!_1 *H$
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。 1++ Fs
C:full outer join: atfK?VK#
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。 \
id(P3M
FVoKNaK-
+L}R|ihkI
二、提升 G#z9=NF~V
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) hhr>nuA
法一:select * into b from a where 1<>1 Um
I,?p
法二:select top 0 * into b from a 4_vJ_H-mO,
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ]iiB|xT
insert into b(a, b, c) select d,e,f from b; wafws*b%
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) !9=Y(rb
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 6E:5w9_=c
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. r Ww.(l
4、说明:子查询(表名1:a 表名2:b) izr
3{y5
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) X#u< 3<P
5、说明:显示文章、提交人和最后回复时间 2H`;?#Uq:
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b vb k4
6、说明:外连接查询(表名1:a 表名2:b) :j%
B(@b
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c kX'a*AG
7、说明:在线视图查询(表名1:a ) KU;m.{
select * from (SELECT a,b,c FROM a) T where t.a > 1; unkA%x{W;
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 X0%BE!
select * from table1 where time between time1 and time2 Z-z(SKL
select a,b,c, from table1 where a not between 数值1 and 数值2 &d[%
9、说明:in 的使用方法 4ak} "Z
select * from table1 where a [not] in ('值1','值2','值4','值6') 3 _c4+u"6
10、说明:两张关联表,删除主表中已经在副表中没有的信息 N+ ei)-
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) LwEc*79
11、说明:四表联查问题: ]4&B*]j
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 ..... A,GJ6qp3
12、说明:日程安排提前五分钟提醒 yI*h"?7T
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 qyYf&VC}
13、说明:一条sql 语句搞定数据库分页 {:BY
IdX
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 ~DK=&hCd!
14、说明:前10条记录 0,[-4m
select top 10 * form table1 where 范围 Bd*\|M
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.) W:=CpbwENX
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ZY> u4v.
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 [$%0[;jtS
(select a from tableA ) except (select a from tableB) except (select a from tableC) 2dBjc{
17、说明:随机取出10条数据 )N]%cO(^
select top 10 * from tablename order by newid() azpXE
18、说明:随机选择记录 [r=U-
select newid() *uZ'MS
19、说明:删除重复记录 lyrwm{&
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) o|c"W}W
20、说明:列出数据库里所有的表名 !EO
2
select name from sysobjects where type='U' AV["%$:
21、说明:列出表里的所有的 [fXC ;c1
select name from syscolumns where id=object_id('TableName') 05vu{>
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。 ou'|e "tI
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 4 {3<
`
显示结果: -*&C "%e
type vender pcs N!=Q]\ZD
电脑 A 1 5[>N[}Ck>
电脑 A 1 dZjh@yGP.
光盘 B 2 2/FH9T;e".
光盘 A 2 3`Q>s;DjIU
手机 B 3 0i9C\'W`
手机 C 3 d`4@aoM
23、说明:初始化表table1 9IG3zM f
TRUNCATE TABLE table1 G@Vz
}B:=
24、说明:选择从10到15的记录 ( 0Z3Ksfj1
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc G@]|/kN1y
O(f&0h
!
9w,u4q
Ry iS
三、技巧 4\EvJg@Z.
1、1=1,1=2的使用,在SQL语句组合时用的较多 N&+DhKw
"where 1=1" 是表示选择全部 "where 1=2"全部不选, mnWbV\ VY
如: W/|C
if @strWhere !='' @V#
wYt
begin 9]TvLh3
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere "t)|N
dZm
end ;X2 (G
else J*CfG;Y:
begin Oe%jV,S |V
set @strSQL = 'select count(*) as Total from [' + @tblName + ']'
I`}<1~ue
end Qz?r4kR
我们可以直接写成 4 '-GcH
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere HxH=~B1"P
2、收缩数据库 s_ N]$3'[E
--重建索引 h ^6Yjy
DBCC REINDEX 2VNfnk
DBCC INDEXDEFRAG 66~]7w
--收缩数据和日志 Dhe ]f#d
DBCC SHRINKDB -, #LTW<.
DBCC SHRINKFILE BHBMMjY5
3、压缩数据库 *]_GFixi
dbcc shrinkdatabase(dbname) 4FgY!k
4、转移数据库给新用户以已存在用户权限 `mTc
exec sp_change_users_login 'update_one','newname','oldname' r=ds'n"
go 7Y(ySW
5、检查备份集 L]HYk}oD.
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' tqo!WuZAj
6、修复数据库 Z'sO9Sg8>
ALTER DATABASE [dvbbs] SET SINGLE_USER ';bovh@*
GO ZM%z"hO9R
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ,0Y5O?pu\
GO RDu'N
ALTER DATABASE [dvbbs] SET MULTI_USER m}3POl/*j
GO B>&eciY
7、日志清除 .8%mi'0ud
SET NOCOUNT ON )vFZl]
DECLARE @LogicalFileName sysname, (e;9,~u)
@MaxMinutes INT, P>t[35/1
@NewSize INT U)N_/
USE tablename -- 要操作的数据库名 6|D,`dk3U
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 VX;tglu2
@MaxMinutes = 10, -- Limit on time allowed to wrap log. #D{//P|;
@NewSize = 1 -- 你想设定的日志文件的大小(M) gZr/Dfy
-- Setup / initialize O/=i'0Xv
DECLARE @OriginalSize int ;Q =EI%_tv
SELECT @OriginalSize = size kDG'5X;+
FROM sysfiles jHx<}<
WHERE name = @LogicalFileName :i6k6=
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ;|LS$O1c
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + $yx34=
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' sR. ecs+
FROM sysfiles /U%Xs}A)
WHERE name = @LogicalFileName S qQqG3F
CREATE TABLE DummyTrans sm>Hkci%
(DummyColumn char (8000) not null) afMIq Q?
DECLARE @Counter INT, ^f,('0p->
@StartTime DATETIME, XHlx89v7
@TruncLog VARCHAR(255) +$+'|w
SELECT @StartTime = GETDATE(), n'#(iW)f
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ,JcQp=g
DBCC SHRINKFILE (@LogicalFileName, @NewSize) E@_M|=p&
EXEC (@TruncLog) nJ4CXSdE
-- Wrap the log if necessary. e1RtoNF ^
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ;U|^Tsuc`
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) J
dDP
AND (@OriginalSize * 8 /1024) > @NewSize df7z&{R
BEGIN -- Outer loop. THmX=K4=?
SELECT @Counter = 0 ZK[S'(6q
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) &:` 7
BEGIN -- update ^E7>!Lbvx
INSERT DummyTrans VALUES ('Fill Log') ?)cNe:KY
DELETE DummyTrans $[Fh|%\
SELECT @Counter = @Counter + 1 ntSPHK|'
END ;Db89Nc$
EXEC (@TruncLog) o"x&F
END {O,Cc$_
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 96Tc:#9i
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + m GWT</=[$
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' "l&sDh%Lk<
FROM sysfiles &0
VM <
WHERE name = @LogicalFileName {=,?]Z+
DROP TABLE DummyTrans rY>{L6d
SET NOCOUNT OFF 15r<n
8、说明:更改某个表 `
m`Sl[6
exec sp_changeobjectowner 'tablename','dbo' Iy](?b
9、存储更改全部表 5}R/C{fs
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch &:-`3J-
@OldOwner as NVARCHAR(128), $s hlNW\
@NewOwner as NVARCHAR(128) zy#E qv
AS gTR:9E:B
DECLARE @Name as NVARCHAR(128) id.o)=
DECLARE @Owner as NVARCHAR(128) L$`!~z1
DECLARE @OwnerName as NVARCHAR(128) A]{8=
DECLARE curObject CURSOR FOR &Sc}3UI/F
select 'Name' = name, c(bh i
'Owner' = user_name(uid) C<6IiF[>%
from sysobjects 3Nh;^
where user_name(uid)=@OldOwner 0rT-8iJp4P
order by name flLC\
OPEN curObject J680|\ ER
FETCH NEXT FROM curObject INTO @Name, @Owner #TUsi,jG
WHILE(@@FETCH_STATUS=0) ~S
R:,R
BEGIN XQk9 U
if @Owner=@OldOwner H+; _fd
begin sf?D4UdIH
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ;1cX|N=
exec sp_changeobjectowner @OwnerName, @NewOwner /s=TLPm
end r! 5C3
-- select @name,@NewOwner,@OldOwner
CD^_>sya
FETCH NEXT FROM curObject INTO @Name, @Owner _SC>EP8:Z
END R$*{@U
close curObject QH4nb h4
deallocate curObject )E^4\3^:
GO Ckvm3r\i2
10、SQL SERVER中直接循环写入数据 mB#`{|1[
declare @i int ;X\>oV3#
set @i=1 Vd|5JA}<"
while @i<30 X63DBF4A
begin >U9!KB
insert into test (userid) values(@i) LIVVb"V|,
set @i=@i+1 /PIU@$DV
end >.#uoW4ZV
小记存储过程中经常用到的本周,本月,本年函数 JPiC/
Dateadd(wk,datediff(wk,0,getdate()),-1) '&3Sl?E
Dateadd(wk,datediff(wk,0,getdate()),6) \nx^=4*yk
Dateadd(mm,datediff(mm,0,getdate()),0) Xt8;Pl
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 1(!!EcU_
Dateadd(yy,datediff(yy,0,getdate()),0) bs]ret$?(q
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 5\f*xY
上面的SQL代码只是一个时间段 qB7.LR*'
Dateadd(wk,datediff(wk,0,getdate()),-1) DSy,#yA
Dateadd(wk,datediff(wk,0,getdate()),6) /Yx 1S'5
就是表示本周时间段. mxQS9y
下面的SQL的条件部分,就是查询时间段在本周范围内的: s+^o[R
T3
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) >lyUr*4PX
而在存储过程中 X<(h)&E
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) k KL^U
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) (J<@e!@NE