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。 L_}F.nbS5
Xldz&&@
>w|2 ~oK
一、基础 8\CmM\R
1、说明:创建数据库 x%,!px3s
CREATE DATABASE database-name "y=AVO
2、说明:删除数据库 F6-U{+KU$!
drop database dbname r r(UE
3、说明:备份sql server JAI ;7
--- 创建 备份数据的 device Eb9{
USE master hB-<GGcO <
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' M}`G}*
--- 开始 备份 b "5WsJ:'#
BACKUP DATABASE pubs TO testBack (c9!:
4、说明:创建新表 @]B
7(j<'R
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) C9E@$4*
根据已有的表创建新表: nh%Q";
A:create table tab_new like tab_old (使用旧表创建新表) t}-rN5GO
B:create table tab_new as select col1,col2... from tab_old definition only D2Dk7//82Y
5、说明:删除新表 G:{\-R'
drop table tabname r#/Bz5Jb*
6、说明:增加一个列 \FjY;rqfKe
Alter table tabname add column col type ;.b^A
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 firiYL"=44
7、说明:添加主键: Alter table tabname add primary key(col) B e2yS]U
说明:删除主键: Alter table tabname drop primary key(col) BI0 A0
8、说明:创建索引:create [unique] index idxname on tabname(col....) IP l]$j>N
删除索引:drop index idxname VHTr;(]hk
注:索引是不可更改的,想更改必须删除重新建。 [7gwJiK
9、说明:创建视图:create view viewname as select statement +xRSd *
删除视图:drop view viewname gq an]b_
10、说明:几个简单的基本的sql语句 ;>B06v
选择:select * from table1 where 范围 3dC;B@
插入:insert into table1(field1,field2) values(value1,value2) k^r-~q+NV#
删除:delete from table1 where 范围 KVCj06}j
更新:update table1 set field1=value1 where 范围 gD/% l[
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 6O'6,%#
排序:select * from table1 order by field1,field2 [desc] ?$AWY\
总数:select count as totalcount from table1 ~[4zm$R^
求和:select sum(field1) as sumvalue from table1 )>rHM6-W
平均:select avg(field1) as avgvalue from table1 {Qj7?}xW
最大:select max(field1) as maxvalue from table1 }A'Ro/n
最小:select min(field1) as minvalue from table1
BH`GUIk
nN!R!tJPa
xsSX~`
>X-*Hu'U#
11、说明:几个高级查询运算词 ,{u'7p
'.d]n(/lZd
%&b70]S(
A: UNION 运算符 =hB0p^a
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。 7NDjXcuq
B: EXCEPT 运算符 8S7 YVsDz"
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。 [49Ae2W`
C: INTERSECT 运算符 ${)s
~[
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。
hDHIi\%
注:使用运算词的几个查询结果行必须是一致的。 vP{;'R
12、说明:使用外连接 P0XVR_TJf
A、left outer join: bdkxCt
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。 1PjqXgN5p
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 Blnc y
B:right outer join: LjMhPzCp
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。 |!H@{o
C:full outer join: }?XNA.Wz
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。 lT~A~O
]<?7CpP
088"7 s
二、提升 u3@v
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) F otHITw[
法一:select * into b from a where 1<>1 _f@,
>l
法二:select top 0 * into b from a D^e7%FX
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) :T# "bY
insert into b(a, b, c) select d,e,f from b; ;#Pc^Yzc1
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) DB;Nr3x
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 61{IXx_
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. F_C_K"[s
4、说明:子查询(表名1:a 表名2:b) *;yn_zg
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) gTjhD(
5、说明:显示文章、提交人和最后回复时间 /yS/*ET8
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b !E|k#c9
6、说明:外连接查询(表名1:a 表名2:b) bjYaJtn
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c #Do#e
{=+
7、说明:在线视图查询(表名1:a ) uw`fC%-xh
select * from (SELECT a,b,c FROM a) T where t.a > 1; 26<Wg7/,
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 W;@9x1jKX
select * from table1 where time between time1 and time2 k=):>}
select a,b,c, from table1 where a not between 数值1 and 数值2 Y;6%pm $
9、说明:in 的使用方法 @%sr#YqY
select * from table1 where a [not] in ('值1','值2','值4','值6') 1I -LGe[Q
10、说明:两张关联表,删除主表中已经在副表中没有的信息 .WT^L2l%
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) kw.IVz<
11、说明:四表联查问题: mFXkrvOf,
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 ..... ?\$\YX%/p
12、说明:日程安排提前五分钟提醒 [.`%]Z(
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 q^k]e{PD
13、说明:一条sql 语句搞定数据库分页 Ps_q\R
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 Z-B b,8
14、说明:前10条记录 &b7i> ()
select top 10 * form table1 where 范围 +Jv*u8T'
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.) C^ hCT
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) aR~Od Ys
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 Oe[qfsdW
(select a from tableA ) except (select a from tableB) except (select a from tableC) .&Ok53]b
17、说明:随机取出10条数据 xRU ~hQ
select top 10 * from tablename order by newid() duk:: |{F
18、说明:随机选择记录 KGoHn6jM
select newid() ,Y3wXmG
19、说明:删除重复记录 I_h{n{,sr
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 81<0B@E
20、说明:列出数据库里所有的表名 X0"f>.Lg
select name from sysobjects where type='U' hpVu
21、说明:列出表里的所有的 Qo;#}%}^^
select name from syscolumns where id=object_id('TableName') 8${Yu
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 eX@7f!uz
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type J\ V.J/
显示结果: 3Ta<7tEM
type vender pcs {BlKVsQ
电脑 A 1 Ud8*yB
电脑 A 1 ';hTGLq\X
光盘 B 2 xFY<
ns
光盘 A 2 ~1yMw.04V
手机 B 3 bhb*,iWA
手机 C 3 !(wH}ti
23、说明:初始化表table1 k;9"L90
TRUNCATE TABLE table1 2og8VI
24、说明:选择从10到15的记录 =!cI@TI
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc @\UoZv(
>)IXc<"wq
7berkU0P
%g<J"/
三、技巧 }_{QsPx9
1、1=1,1=2的使用,在SQL语句组合时用的较多
(s\":5
C
"where 1=1" 是表示选择全部 "where 1=2"全部不选, /-W-MP=Wd
如: > \KVg(?D
if @strWhere !='' r\-25F<e5
begin hIr$^%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere yw(E}
end k v}<u
else 23;e/Qr
begin BOQeP/>
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' _2,eS[wP
end <?I s ~[2
我们可以直接写成 u70-HFI@
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere [8K+zT5
2、收缩数据库 v 8`)h<:W?
--重建索引 Twj?SV
DBCC REINDEX M5Twulz/w
DBCC INDEXDEFRAG 'C9H6)Zq)
--收缩数据和日志 oYG].PC
DBCC SHRINKDB gAY%VFBP0
DBCC SHRINKFILE dTV:/QM
3、压缩数据库 O(( kv|X4
dbcc shrinkdatabase(dbname) !^|%Z
4、转移数据库给新用户以已存在用户权限 VnJ-nfA
exec sp_change_users_login 'update_one','newname','oldname' ;Q]j"1c
go %YaUc{.%
5、检查备份集 ^3-Wxn9&
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ;^,2
Qs M
6、修复数据库 L8~nx}UP5
ALTER DATABASE [dvbbs] SET SINGLE_USER O&:0mpRZ
GO 7Pc0|Z/
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK w$5N6
GO {xC CUU
ALTER DATABASE [dvbbs] SET MULTI_USER #NVqS5
GO WR*|kh
7、日志清除 Hhbf9)
SET NOCOUNT ON Iy}r'#N
DECLARE @LogicalFileName sysname, $DfaW3bJ
@MaxMinutes INT, J\%<.S>
@NewSize INT .=>T yq
USE tablename -- 要操作的数据库名 P'Fy,fNg
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 hao0_9q+
@MaxMinutes = 10, -- Limit on time allowed to wrap log. |-zwl8E
@NewSize = 1 -- 你想设定的日志文件的大小(M) sX&M+'h
-- Setup / initialize S%ri/}qI[{
DECLARE @OriginalSize int :`Kr|3bQ
SELECT @OriginalSize = size @HfWAFT
FROM sysfiles RT45@
WHERE name = @LogicalFileName {tE/Jv $
SELECT 'Original Size of ' + db_name() + ' LOG is ' + %(-YOTDr
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + lK^Q#td:`
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' :{9|/a
FROM sysfiles [hg|bpEG
WHERE name = @LogicalFileName T2wn!N?r
CREATE TABLE DummyTrans afEp4(X~
(DummyColumn char (8000) not null) f/b }X3K
DECLARE @Counter INT, -?b@ 6U
@StartTime DATETIME, ;UgRm#
@TruncLog VARCHAR(255) L-d8bA
SELECT @StartTime = GETDATE(), c=2e?
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' *x|
<\_+
DBCC SHRINKFILE (@LogicalFileName, @NewSize) {zGIQG9
EXEC (@TruncLog) OvPy+I
-- Wrap the log if necessary. V=|^r?
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Y\T*8\h_[
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) rI}E2J
AND (@OriginalSize * 8 /1024) > @NewSize ~zz |U!TG
BEGIN -- Outer loop. =3=KoH/'
SELECT @Counter = 0 zJMKgw,i*
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000))
hh"0z]
BEGIN -- update );h\0w>3
INSERT DummyTrans VALUES ('Fill Log') Z"gllpDr$
DELETE DummyTrans oQDOwM,
SELECT @Counter = @Counter + 1 JLAg-j2
END #{0DpSzE5
EXEC (@TruncLog) 81_3{OrE<
END D,eJR(5I
SELECT 'Final Size of ' + db_name() + ' LOG is ' + |Z;wk&
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + $EJ*x$
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' |?Q(4(D`*
FROM sysfiles u,F d[[t
WHERE name = @LogicalFileName nRQIrUNq
DROP TABLE DummyTrans xgR* j
SET NOCOUNT OFF 7o
z(hO~
8、说明:更改某个表 Ut-6!kAm
exec sp_changeobjectowner 'tablename','dbo' >B~jPU
9、存储更改全部表 =DxJt7J1
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch y`Pp"!P"O
@OldOwner as NVARCHAR(128), <nsl`C~6g0
@NewOwner as NVARCHAR(128) l1cBY{3QD
AS LbR/it'}
DECLARE @Name as NVARCHAR(128) RQ,(?I*8\
DECLARE @Owner as NVARCHAR(128) >`NY[Mn
DECLARE @OwnerName as NVARCHAR(128) b=T+#Jb
DECLARE curObject CURSOR FOR VP 4t~$"
select 'Name' = name, |->y'V
'Owner' = user_name(uid) UKK}$B
from sysobjects M{kPEl&Z
where user_name(uid)=@OldOwner 6sy%KO*A
order by name F'CUkVC0~P
OPEN curObject >2syF{`j
FETCH NEXT FROM curObject INTO @Name, @Owner f9- |!]s
WHILE(@@FETCH_STATUS=0) 8
(^2
BEGIN >KY\Bx
if @Owner=@OldOwner >q &ouVE
begin *A\NjXJl~
set @OwnerName = @OldOwner + '.' + rtrim(@Name) SA>;]6)`(
exec sp_changeobjectowner @OwnerName, @NewOwner .%wEuqW=0
end )Qxv9:X
-- select @name,@NewOwner,@OldOwner 0acY@_
FETCH NEXT FROM curObject INTO @Name, @Owner xYu~}kMu
END @?]-5 ~3;
close curObject g&0GO:F`
deallocate curObject 4_.k Q"'DH
GO K[sM)_I
10、SQL SERVER中直接循环写入数据 ?XOeMI
declare @i int T%a]3
set @i=1 j|G-9E
while @i<30 oZCi_g 5i
begin g41Lh3dj
insert into test (userid) values(@i) gy =`c MS@
set @i=@i+1 ` 4EOy:a
end z~
u@N9M
小记存储过程中经常用到的本周,本月,本年函数 !RcAJs'
Dateadd(wk,datediff(wk,0,getdate()),-1) 8]?1gDS|9O
Dateadd(wk,datediff(wk,0,getdate()),6) 3Xh&l[.
Dateadd(mm,datediff(mm,0,getdate()),0) [S4\fy0
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) *VlYl"
Dateadd(yy,datediff(yy,0,getdate()),0) M.8!BB7\8e
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 'c$9[|x
上面的SQL代码只是一个时间段 ,;d9uG2
Dateadd(wk,datediff(wk,0,getdate()),-1) mTP.W#N
Dateadd(wk,datediff(wk,0,getdate()),6) [d&Faa[`
就是表示本周时间段. Fcr@Un'
下面的SQL的条件部分,就是查询时间段在本周范围内的: fd,~Yj$R?
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) oM7^h3R
而在存储过程中 |(P;2q4>
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) CLk Ve
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 0KQ8;&a|