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。 IH;sVT$M
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一、基础 <(q(5jG
1、说明:创建数据库 ]'`E
CREATE DATABASE database-name m/1FVC@*
2、说明:删除数据库 &s='$a;4
drop database dbname UWF
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3、说明:备份sql server [Q0V 5P~Q'
--- 创建 备份数据的 device yo=L1;H
USE master {u/1ph-
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Y@`uBB[
--- 开始 备份 >Jmla~A
BACKUP DATABASE pubs TO testBack c3 O/#*
4、说明:创建新表 7IkPi?&{
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 2}A)5P*K
根据已有的表创建新表: HMCLJ/
A:create table tab_new like tab_old (使用旧表创建新表) ;U|(rM;
B:create table tab_new as select col1,col2... from tab_old definition only $uZmIu9Bi+
5、说明:删除新表 `R$i|,9)
drop table tabname CtXbAcN2B
6、说明:增加一个列 V6X )L>!xx
Alter table tabname add column col type @^<odmM
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。 \y5lYb,*c_
7、说明:添加主键: Alter table tabname add primary key(col) jZ|M$I3*
说明:删除主键: Alter table tabname drop primary key(col) !1G
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8、说明:创建索引:create [unique] index idxname on tabname(col....) W!wof-1
删除索引:drop index idxname $G-<kC}8:
注:索引是不可更改的,想更改必须删除重新建。 KGYbPty}
9、说明:创建视图:create view viewname as select statement ?1D!%jfi
删除视图:drop view viewname :Ln)j%&
10、说明:几个简单的基本的sql语句 |gA@WV-%
选择:select * from table1 where 范围 (T_-`N|
插入:insert into table1(field1,field2) values(value1,value2) hO]F\0+
删除:delete from table1 where 范围 3uocAmY
更新:update table1 set field1=value1 where 范围 z.Ic?Wz7
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! bGCC?}\
排序:select * from table1 order by field1,field2 [desc] 1EXT^2!D
总数:select count as totalcount from table1 >jX"
求和:select sum(field1) as sumvalue from table1 68XJ`/d
平均:select avg(field1) as avgvalue from table1 c|k_[8L
最大:select max(field1) as maxvalue from table1 2n,z`(=
最小:select min(field1) as minvalue from table1 k1<^Ept
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11、说明:几个高级查询运算词 [(heE
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A: UNION 运算符 AH#mL
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。 %):_
B: EXCEPT 运算符 cu N9RG
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。 Gr\ ]6
C: INTERSECT 运算符 A?H#bRAs
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。 1zPS#K/3
注:使用运算词的几个查询结果行必须是一致的。 8>9Mh!t}(I
12、说明:使用外连接 Z)s
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A、left outer join: hzsQK_;S
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。 2iG+Ek-?"
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 &VGV0K3Dp
B:right outer join: <= o<lRU
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。 ~_fc=^o
C:full outer join: "V' r}>
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。 N1Vj;-
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二、提升 Y~vk>ZC
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) @Chl>s
法一:select * into b from a where 1<>1 Sb[>R(0:
法二:select top 0 * into b from a &<N8d(
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ',r` )9o
insert into b(a, b, c) select d,e,f from b; I?'*vAW<
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) b* n3Fej
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ,D;8~llM
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. _d]{[&
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4、说明:子查询(表名1:a 表名2:b) ^
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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) )/jDt dI
5、说明:显示文章、提交人和最后回复时间 TRi'l #m4
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 8J3#(aBm
6、说明:外连接查询(表名1:a 表名2:b) ]`$6=)_X
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c _<(xjWp 8
7、说明:在线视图查询(表名1:a ) $VmV>NZ
select * from (SELECT a,b,c FROM a) T where t.a > 1; peVY2\1>R
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 oJTEN}fL
select * from table1 where time between time1 and time2 ';3>rv_
select a,b,c, from table1 where a not between 数值1 and 数值2 /(^-=pAX
9、说明:in 的使用方法 4;6"I2;zfG
select * from table1 where a [not] in ('值1','值2','值4','值6') =3035{\
10、说明:两张关联表,删除主表中已经在副表中没有的信息 nX (bVT4i
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) }k VC]+
11、说明:四表联查问题: }dN\bb{#
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 ..... tx5bmF;b)
12、说明:日程安排提前五分钟提醒 xw8k<`
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Yh1</C
13、说明:一条sql 语句搞定数据库分页 6]1RxrAV
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 S%\5"uGa
14、说明:前10条记录 +ywz@0nx
select top 10 * form table1 where 范围 jr`T6!\
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.) ]Ozz"4Z
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) E{Wn&?i>A
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 k9
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(select a from tableA ) except (select a from tableB) except (select a from tableC) c +]r
17、说明:随机取出10条数据 I0F[Z\U
select top 10 * from tablename order by newid() ~T@E")uR
18、说明:随机选择记录 E<yQB39
select newid() (d&" @
19、说明:删除重复记录 4BMu0["6|s
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) f/sz/KC]~
20、说明:列出数据库里所有的表名 2!6hB sEr
select name from sysobjects where type='U' dEDhdF#f
21、说明:列出表里的所有的 U<=TAWZ@
select name from syscolumns where id=object_id('TableName') /(~
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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。 Nf4@m|#
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 aG7Lm2{c"
显示结果: OAkqPG&w
type vender pcs @wXYza0|d
电脑 A 1 ":eyf3M
电脑 A 1 I;XM4a
光盘 B 2 XO;_F"H=
光盘 A 2 `lY-/Ty
手机 B 3 r.?dT |A
手机 C 3 a0ms9%Y;Q[
23、说明:初始化表table1 ;rf{T[i
TRUNCATE TABLE table1 :7(fBf5
24、说明:选择从10到15的记录 Sqp91[,
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc L[zTT\a
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三、技巧 dU-:#QV6
1、1=1,1=2的使用,在SQL语句组合时用的较多 QHv]7&^rlj
"where 1=1" 是表示选择全部 "where 1=2"全部不选, qg j;E=7
如: Z%?>H iy'o
if @strWhere !='' GNW$:=0u
begin y0 vo-Q
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere w8+phN(-M
end d*u3]&?x&f
else %;wDB2k*
begin %{ U (y#
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' @^0}w k
end !v3d:n\W8
我们可以直接写成 &v]xYb)+<
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 6<z#*`U1
2、收缩数据库 jXx~5
--重建索引 /\ fR6|tJ
DBCC REINDEX sB0]lj-[Un
DBCC INDEXDEFRAG fbI5!i#lz
--收缩数据和日志 iw.F8[})
DBCC SHRINKDB "U9e)a0v
DBCC SHRINKFILE ~e|E5[-i
3、压缩数据库 <YCjo[(~
dbcc shrinkdatabase(dbname) GB+$ed5@<
4、转移数据库给新用户以已存在用户权限 7IUJHc[R?
exec sp_change_users_login 'update_one','newname','oldname' vmxS^_I
go ^E,
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5、检查备份集 l )r^|9{
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 0]ai*\,W7~
6、修复数据库 yu#m6K
ALTER DATABASE [dvbbs] SET SINGLE_USER `_&vvJPn@!
GO 1&h\\&ic
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK nVpDjUpN
GO wI7.M
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ALTER DATABASE [dvbbs] SET MULTI_USER yTc&C)Jba
GO HZ(giAyjq
7、日志清除 a"cw%L
SET NOCOUNT ON {dh@|BzsbH
DECLARE @LogicalFileName sysname, Wu,=jL3?$A
@MaxMinutes INT, F`;q9<NYRW
@NewSize INT &gh>'z;`r
USE tablename -- 要操作的数据库名 ht\_YiDg3
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 :EPe,v RT
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 7LaRFL.,kO
@NewSize = 1 -- 你想设定的日志文件的大小(M) M3eSj`c3
-- Setup / initialize BD$Lf,_
DECLARE @OriginalSize int J^WX^".E
SELECT @OriginalSize = size dR s\e(H'
FROM sysfiles #- L <
WHERE name = @LogicalFileName >xRUw5jN
SELECT 'Original Size of ' + db_name() + ' LOG is ' + "SuG6!k3
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + _+}o/449
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 2(Xu?W 7d
FROM sysfiles !FK)iQy$0
WHERE name = @LogicalFileName (Rs;+S
CREATE TABLE DummyTrans &/Gf@[
(DummyColumn char (8000) not null) U8aNL
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DECLARE @Counter INT, 3W[||V[r]<
@StartTime DATETIME, .'
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@TruncLog VARCHAR(255) Gp_flGdGQ
SELECT @StartTime = GETDATE(), i1{)\/f3
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ^Ux.s Q
DBCC SHRINKFILE (@LogicalFileName, @NewSize) {Zs
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EXEC (@TruncLog) njNqUo>
-- Wrap the log if necessary. ra
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired K6F05h 5S
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) E.B6u, Te
AND (@OriginalSize * 8 /1024) > @NewSize A'uubFRL2[
BEGIN -- Outer loop. cr18`xU
SELECT @Counter = 0 IUWJi\,
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) PE_JO(e;Xm
BEGIN -- update n-?zH:]GG{
INSERT DummyTrans VALUES ('Fill Log') B0g?!.#23
DELETE DummyTrans uxX 3wY;M
SELECT @Counter = @Counter + 1 \R
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END >kuu\
EXEC (@TruncLog) DLq'V.M:
END .5~3D97X&
SELECT 'Final Size of ' + db_name() + ' LOG is ' + -Zg.o$
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Lm^vS u
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' | @B|o-
FROM sysfiles V2yX;u
WHERE name = @LogicalFileName G[d]t$f=
DROP TABLE DummyTrans 6 G,cc
SET NOCOUNT OFF zo
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8、说明:更改某个表 V\c`O
exec sp_changeobjectowner 'tablename','dbo' IUG}Q7w5
9、存储更改全部表 X2 <fS~m
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ;+3@S`2r
@OldOwner as NVARCHAR(128), /*6[Itm_h
@NewOwner as NVARCHAR(128) do.XMdit
AS |*~SR.[`
DECLARE @Name as NVARCHAR(128) (76tYt~I=
DECLARE @Owner as NVARCHAR(128) nGDY::nUE
DECLARE @OwnerName as NVARCHAR(128) &`g^b^i
DECLARE curObject CURSOR FOR H-%
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select 'Name' = name, WxJaE;`Ige
'Owner' = user_name(uid) %4wHiCOg
from sysobjects Nah\4-75&
where user_name(uid)=@OldOwner 8yswi[
order by name b$/7rVH!
OPEN curObject y?iW^>|?L=
FETCH NEXT FROM curObject INTO @Name, @Owner !@h)3f]`1G
WHILE(@@FETCH_STATUS=0) MbQ%'z6D
BEGIN WQ{^+C9g'1
if @Owner=@OldOwner {(d 6of`C_
begin #A~7rH%hi
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 5sB~.z@
exec sp_changeobjectowner @OwnerName, @NewOwner b.
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end T#}"?A|
-- select @name,@NewOwner,@OldOwner GG4FS
FETCH NEXT FROM curObject INTO @Name, @Owner Jg&f.
END U*BI/wZ
close curObject $GD
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deallocate curObject u`*1OqU
GO usU6,
10、SQL SERVER中直接循环写入数据 %mS>v|
declare @i int iML?`%/vN
set @i=1 'kJyE9*xU.
while @i<30 K7,Sr1O `
begin y+',jM
insert into test (userid) values(@i) K:$GmV9o
set @i=@i+1 3my_Gp
end A*kN
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小记存储过程中经常用到的本周,本月,本年函数 *"V) hI5
Dateadd(wk,datediff(wk,0,getdate()),-1) u&j_;Y !6
Dateadd(wk,datediff(wk,0,getdate()),6) $b) k
Dateadd(mm,datediff(mm,0,getdate()),0) ] $F%
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) =s:Z-*vy!
Dateadd(yy,datediff(yy,0,getdate()),0) `{ \)Wuw
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 0|mCk
上面的SQL代码只是一个时间段 BtF7P}:MGf
Dateadd(wk,datediff(wk,0,getdate()),-1) !#4b#l(e6
Dateadd(wk,datediff(wk,0,getdate()),6) 1#XZVp;M
就是表示本周时间段. ddlF4L_
下面的SQL的条件部分,就是查询时间段在本周范围内的: j9f Q V
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) "i%=QON`
而在存储过程中 HC$}KoZkC
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) A4)TJY
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 5_rx$avm