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。 ICoHI
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一、基础 NP#w+Qw
1、说明:创建数据库 /k6MzFoid
CREATE DATABASE database-name *{@Nq=fE
2、说明:删除数据库 c9'vDTE%~
drop database dbname KB,j7
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3、说明:备份sql server ;|5F[
--- 创建 备份数据的 device zh`<WN&H
USE master wj<6kG
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Eh;'S"{/?j
--- 开始 备份 # E^1|:
BACKUP DATABASE pubs TO testBack fue(UMF~
4、说明:创建新表 SSg8}m5)Q
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) dA`IEQJL
根据已有的表创建新表: E7 Ul;d
A:create table tab_new like tab_old (使用旧表创建新表) 3cyHfpx-W
B:create table tab_new as select col1,col2... from tab_old definition only p8H'{f\G
5、说明:删除新表 .fFCC`&T
drop table tabname A*R^n}sh
6、说明:增加一个列 ZW8vza
Alter table tabname add column col type y8Z_Itlf
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。 }wjw:M
7、说明:添加主键: Alter table tabname add primary key(col) "3"V3w
说明:删除主键: Alter table tabname drop primary key(col) N1S{suic
8、说明:创建索引:create [unique] index idxname on tabname(col....) vq0Tk
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删除索引:drop index idxname gA+qC7=p$
注:索引是不可更改的,想更改必须删除重新建。 &yTqZ*Yuk
9、说明:创建视图:create view viewname as select statement +z\^t_"f
删除视图:drop view viewname 9y8&9<#
10、说明:几个简单的基本的sql语句 S6M}WR^,
选择:select * from table1 where 范围 +nhLIO{{L
插入:insert into table1(field1,field2) values(value1,value2) Mj?`j_X
删除:delete from table1 where 范围 /-qNh>v4
更新:update table1 set field1=value1 where 范围 :&rt)/I
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! k&q;JyUi
排序:select * from table1 order by field1,field2 [desc] <QAFL uey
总数:select count as totalcount from table1 V-2(?auZd
求和:select sum(field1) as sumvalue from table1 v0+BkfU+p
平均:select avg(field1) as avgvalue from table1 4qh?,^Dq
最大:select max(field1) as maxvalue from table1 D~fl JR
最小:select min(field1) as minvalue from table1 cJ
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11、说明:几个高级查询运算词 m@F`!qY~Y\
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A: UNION 运算符 y`5
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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。 Jr!JHC9i
B: EXCEPT 运算符 D~iz+{Q4
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。 Uh4%}-;
C: INTERSECT 运算符 !bx;Ta.
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。 e8!5I,I
注:使用运算词的几个查询结果行必须是一致的。 8oseYH
12、说明:使用外连接 ")5":V~fN
A、left outer join: Al^d$FaF
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。 l
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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 {n.PF8A5X
B:right outer join: El".I?E*
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。 7\[@m3s
C:full outer join: M}-Rzc
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。 |?xN\O^#}
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二、提升 8)3*6+D
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) cN6X#D
法一:select * into b from a where 1<>1 EhvX)s
法二:select top 0 * into b from a %y[h5*y*
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) DGF5CK.O
insert into b(a, b, c) select d,e,f from b; CL;}IBd a
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) ~.nmI&3
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 JPUW6e07o
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. a:`E0}C
4、说明:子查询(表名1:a 表名2:b) 8z`G,qh
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) 4G0m\[Du
5、说明:显示文章、提交人和最后回复时间 (Q!}9K3
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b .},'~NM]
6、说明:外连接查询(表名1:a 表名2:b) 7`Ak)F:V
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c h0f;F@I
7、说明:在线视图查询(表名1:a ) ~?Pw& K2
select * from (SELECT a,b,c FROM a) T where t.a > 1; 6OIte-c
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 eA ?RK.e
select * from table1 where time between time1 and time2 I)[DTCJ~
select a,b,c, from table1 where a not between 数值1 and 数值2 $G+@_'
9、说明:in 的使用方法 ~P,lz!he_
select * from table1 where a [not] in ('值1','值2','值4','值6') ,HV(l+k {|
10、说明:两张关联表,删除主表中已经在副表中没有的信息 0<@KG8@hI;
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) YnMvl
11、说明:四表联查问题: RJ&RTo
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 ..... lh7#t#
12、说明:日程安排提前五分钟提醒 ?4&e;83_#y
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 vWv"
13、说明:一条sql 语句搞定数据库分页 rfJz8uF%
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 $6 9&O
14、说明:前10条记录 lU\[aNs
select top 10 * form table1 where 范围 ]^7@}Ce_
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.) ^|(LAjet
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) `25yE/
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 gO- _
(select a from tableA ) except (select a from tableB) except (select a from tableC)
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17、说明:随机取出10条数据 7U"g3a)=
select top 10 * from tablename order by newid() Pn1^NUMZJ
18、说明:随机选择记录 783,s_
select newid() U_Ptqqt%
19、说明:删除重复记录 -f^tE,-
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) P4'Q/Sj
20、说明:列出数据库里所有的表名 I6av6t}
select name from sysobjects where type='U' p)-^;=<B3
21、说明:列出表里的所有的 q3N
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select name from syscolumns where id=object_id('TableName') o#Dk&
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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。 ED( Sg
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 ..5CC;B
显示结果: + GN(Ug'R
type vender pcs ]Q1yNtN
电脑 A 1 _6hQ %hv8
电脑 A 1 ;`{H!w[D
光盘 B 2 'GWN~5
光盘 A 2 |aS.a&vwR
手机 B 3 b. '-?Nn
手机 C 3 P3=G1=47U
23、说明:初始化表table1 Iyn(?w
TRUNCATE TABLE table1 #gN&lY:CFn
24、说明:选择从10到15的记录 bsli0FJSh'
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc _J#zY-j
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三、技巧 o:'MpKm
1、1=1,1=2的使用,在SQL语句组合时用的较多 GL}]y -f
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ec;o\erPG
如: I$G['`XX/
if @strWhere !='' {dlXLx!B
begin ^uc=f2=>,
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere {}n^cq
end iWkWR"ysy
else h,N?Ab'S
begin Ic<2QknmP
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Wvh#:Z
end ebhXak[w
我们可以直接写成 u&vf+6=9Dd
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere khxnlry
2、收缩数据库 +\]\[6
--重建索引
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DBCC REINDEX <'Eme
DBCC INDEXDEFRAG g:@#@1rB6
--收缩数据和日志 *?vCC+c
DBCC SHRINKDB <n$'voR7]
DBCC SHRINKFILE (%6P0*
3、压缩数据库 Nai2W<,
dbcc shrinkdatabase(dbname) Sz`,X0a
4、转移数据库给新用户以已存在用户权限 t3_O H^
exec sp_change_users_login 'update_one','newname','oldname' 0#hlsfc]\
go 1CZgb
5、检查备份集 T7%S
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 6d}lw6L
6、修复数据库 /{_:{G!Q0
ALTER DATABASE [dvbbs] SET SINGLE_USER 9TC,!0U{_.
GO q3!bky\
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK @S;'@VC
GO /,yd+wcW#
ALTER DATABASE [dvbbs] SET MULTI_USER !e<^?
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GO kDioD
7、日志清除 bAqA1y3=
SET NOCOUNT ON .L~AL|2_
DECLARE @LogicalFileName sysname, (w3YvG.
@MaxMinutes INT, 2/^3WY1U
@NewSize INT </zEg3F\
USE tablename -- 要操作的数据库名 C,r;VyW6BI
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 M6jy\<a
@MaxMinutes = 10, -- Limit on time allowed to wrap log. $6 f3F?y7
@NewSize = 1 -- 你想设定的日志文件的大小(M) ^ZcGY+/~
-- Setup / initialize {!L~@r
DECLARE @OriginalSize int /([kh~a
SELECT @OriginalSize = size Lqa4Vi
FROM sysfiles #;yZ
WHERE name = @LogicalFileName =;
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + N4!O.POP
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + x 9fip-
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' P=
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FROM sysfiles -Q*gW2KmV
WHERE name = @LogicalFileName 5t]H?b8
CREATE TABLE DummyTrans a1lh-2xX
(DummyColumn char (8000) not null) q0vQa
DECLARE @Counter INT, kDxFloK
@StartTime DATETIME, u6JM]kR
@TruncLog VARCHAR(255) rEWb"
SELECT @StartTime = GETDATE(), Svmy(w~m
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Y$_B1_
DBCC SHRINKFILE (@LogicalFileName, @NewSize) wc4=VC"y
EXEC (@TruncLog) 0GeTSFj
-- Wrap the log if necessary. usF.bkTp
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 8l`*]1.W<
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) #*Ctwl,T
AND (@OriginalSize * 8 /1024) > @NewSize 4!?eRY
BEGIN -- Outer loop. wmLs/:~
SELECT @Counter = 0 VI86KJu
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ^
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BEGIN -- update 4tBYR9|
INSERT DummyTrans VALUES ('Fill Log') H.MI5O (Q
DELETE DummyTrans "chDg(jMZ
SELECT @Counter = @Counter + 1 Wne@<+mX
END ^1.By^
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EXEC (@TruncLog) S,he6zS
END t{{QE:/
SELECT 'Final Size of ' + db_name() + ' LOG is ' + b\2
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + %'pgGC"|
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' I!K6o.|1
FROM sysfiles j\M?~=*w
WHERE name = @LogicalFileName ?=Kduef
DROP TABLE DummyTrans > ~O.@|
SET NOCOUNT OFF Gd85kY@w7
8、说明:更改某个表 JWxwJex
exec sp_changeobjectowner 'tablename','dbo' gPPkT"
9、存储更改全部表 RA
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch @q)d
@OldOwner as NVARCHAR(128), lThB2/tV\
@NewOwner as NVARCHAR(128) [7y]n;Fy
AS 8":Q)9;%
DECLARE @Name as NVARCHAR(128) SmO~,2=
DECLARE @Owner as NVARCHAR(128) K}Qa~_
DECLARE @OwnerName as NVARCHAR(128) WpvhTX
DECLARE curObject CURSOR FOR %pCTN P
select 'Name' = name, es7=%!0
'Owner' = user_name(uid) &oMh]Z*:
from sysobjects "w<#^d_6
where user_name(uid)=@OldOwner kAUymds;O
order by name ef4 i:.
OPEN curObject ~P-mC@C
FETCH NEXT FROM curObject INTO @Name, @Owner w7L)'9
WHILE(@@FETCH_STATUS=0) 4Z0]oIX
BEGIN G3T]`Atf
if @Owner=@OldOwner |[8Th4*n
begin ~k5W@`"W
set @OwnerName = @OldOwner + '.' + rtrim(@Name) YoFxW5by
exec sp_changeobjectowner @OwnerName, @NewOwner z
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end Q"#J6@
-- select @name,@NewOwner,@OldOwner fk-RV>yr
FETCH NEXT FROM curObject INTO @Name, @Owner 4*;MJ[|
END K|=A:
close curObject I&5!=kR
deallocate curObject m1A J{cs
GO {)<v&'*c~
10、SQL SERVER中直接循环写入数据 Ow,b^|
declare @i int *oix 6
set @i=1 Aos+dP5h,8
while @i<30 #/37V2E
begin $*m-R*kt
insert into test (userid) values(@i) YS_;OFsd
set @i=@i+1 ^iYj[~
end Wd
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小记存储过程中经常用到的本周,本月,本年函数 COlaD"Y
Dateadd(wk,datediff(wk,0,getdate()),-1) Z;"vW!%d
Dateadd(wk,datediff(wk,0,getdate()),6) f|(M.U-
Dateadd(mm,datediff(mm,0,getdate()),0) 6Kz,{F@
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) I]q% 2ie
Dateadd(yy,datediff(yy,0,getdate()),0) 9lE_nc
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) >yDZw!C
上面的SQL代码只是一个时间段 _q^E,P
Dateadd(wk,datediff(wk,0,getdate()),-1) `Q,H|hp;k;
Dateadd(wk,datediff(wk,0,getdate()),6) *VN6cSq
就是表示本周时间段. a8Wwq?@
下面的SQL的条件部分,就是查询时间段在本周范围内的: aw> #P
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) _o~nr]zx
而在存储过程中 ?aMOZn?
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) d/@,@8:
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) <OPArht