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。 WagL8BpLx
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一、基础 s$qc&
1、说明:创建数据库 q
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CREATE DATABASE database-name je2"D7D
2、说明:删除数据库 K]Vp! G
drop database dbname )=X g
3、说明:备份sql server W)J5[p?
--- 创建 备份数据的 device P0(LdZH6u
USE master @1&"S7@}u
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ?u?mSO/
--- 开始 备份 iAk.pH]a
BACKUP DATABASE pubs TO testBack B(vCi^
4、说明:创建新表 &+A78I
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ks6iy}f7
根据已有的表创建新表: n1JV)4Mv
A:create table tab_new like tab_old (使用旧表创建新表) +se OoTKR
B:create table tab_new as select col1,col2... from tab_old definition only 8 >LDo"<
5、说明:删除新表 3**t'iWQ
drop table tabname G4~@
6、说明:增加一个列 U1Fo #L
Alter table tabname add column col type >i >|]
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 8#tuB8>
7、说明:添加主键: Alter table tabname add primary key(col) oF]]Pl{W
说明:删除主键: Alter table tabname drop primary key(col) I=
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8、说明:创建索引:create [unique] index idxname on tabname(col....) koS?UYF`
删除索引:drop index idxname QdcuV\B}
注:索引是不可更改的,想更改必须删除重新建。 &4} =@'G@
9、说明:创建视图:create view viewname as select statement ot2zY
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删除视图:drop view viewname 6__!M
10、说明:几个简单的基本的sql语句 vqQ)Pu?T
选择:select * from table1 where 范围 :[(%4se
插入:insert into table1(field1,field2) values(value1,value2) v0! 1W
删除:delete from table1 where 范围 \}W3\To_
更新:update table1 set field1=value1 where 范围 T?d}IDv1
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! cN?/YkW?]
排序:select * from table1 order by field1,field2 [desc] %+,*$wk#*
总数:select count as totalcount from table1 PN8#T:E
求和:select sum(field1) as sumvalue from table1 $ (xdF
平均:select avg(field1) as avgvalue from table1 c/^jD5U7
最大:select max(field1) as maxvalue from table1 $RRX-
最小:select min(field1) as minvalue from table1 DCZG'eb
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11、说明:几个高级查询运算词 yp^k;G?_d
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A: UNION 运算符 EmrkaV-?k
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 -P|claO0
B: EXCEPT 运算符 W^xO/xu1/
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 [xrsa!$
C: INTERSECT 运算符 ^xNzppz`]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。 3h=kn@I
注:使用运算词的几个查询结果行必须是一致的。 6)?u8K5%r
12、说明:使用外连接 Jq(;BJ90R
A、left outer join: 5Rs#{9YE
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。 Z'2AsT
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 $57Q
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B:right outer join: -ZSN0Xk
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。 N6u>V~i
C:full outer join: S2Ez}*plp
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。 ,.V<rDwN&
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二、提升 G'}N ?8s1
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) dL'oKh,
法一:select * into b from a where 1<>1 I;E?;i
法二:select top 0 * into b from a d_pIB@J
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) .*9u_2<
insert into b(a, b, c) select d,e,f from b; ,"gPd!HD(
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) eIF6f&
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 j\bp#+
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. $H)!h^7^9
4、说明:子查询(表名1:a 表名2:b) )$i,e`T
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) +"BJjxG
5、说明:显示文章、提交人和最后回复时间 [ei~Xkzkj
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b .uS`RS8JM
6、说明:外连接查询(表名1:a 表名2:b) uI?Z_
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c sU*?H`U3d
7、说明:在线视图查询(表名1:a ) :*|Ua%L_
select * from (SELECT a,b,c FROM a) T where t.a > 1; 4TPdq&';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 Op]*wwI*h
select * from table1 where time between time1 and time2 n~\; +U
select a,b,c, from table1 where a not between 数值1 and 数值2 9{Et v w
9、说明:in 的使用方法 RC1bTM
select * from table1 where a [not] in ('值1','值2','值4','值6') u<fZ.1
10、说明:两张关联表,删除主表中已经在副表中没有的信息 >K,QP<B
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Jh&DL8`
11、说明:四表联查问题: M@h"FuX:
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 ..... :n{{\SSIgX
12、说明:日程安排提前五分钟提醒 D^m2iW;
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 0?/gEr
13、说明:一条sql 语句搞定数据库分页 ^zO{A ks
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 sK+uwt
14、说明:前10条记录 9U.Ctx:F
select top 10 * form table1 where 范围 !i (V.A
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.) vw3[(_MV3_
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) |T/OOIA=sI
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 ^c}3o|1m(
(select a from tableA ) except (select a from tableB) except (select a from tableC) N1c0>{
17、说明:随机取出10条数据 GfK%UZ$C
select top 10 * from tablename order by newid() `f&::>5tD
18、说明:随机选择记录 a*X{hU9P
select newid() g3[-[G^5
19、说明:删除重复记录 ([rn.b]
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) _,(s
20、说明:列出数据库里所有的表名 I)` +:+P
select name from sysobjects where type='U' ^VMCs/g6
21、说明:列出表里的所有的 j][&o-Ev
select name from syscolumns where id=object_id('TableName') XPMUhozV
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 >5kz#|@P
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type >%92,hg
显示结果: @Z'i7Z
type vender pcs !xR9I0V5
电脑 A 1 8[X"XThj
电脑 A 1 9%NsW3|
光盘 B 2 yeta)@nH
光盘 A 2 Un)Xe
手机 B 3 Yq|_6zbYf
手机 C 3 S{&%tj~U
23、说明:初始化表table1 ~ <K,P
TRUNCATE TABLE table1 jG{?>^
24、说明:选择从10到15的记录 ;DnUeE8
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc vI(LIfe;
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三、技巧 m`8{arz2
1、1=1,1=2的使用,在SQL语句组合时用的较多 J>T98y/))
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ] WYub1
如: >/4[OPB0R
if @strWhere !='' #V/{DPz
begin 52o^]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere BI,]pf;GWv
end 2Ul8<${c{
else EHf,VIC8
begin `G:1
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' '9.@r\g
end M"s:*c_6
我们可以直接写成 !^MwE]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ue7D'
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2、收缩数据库 \Q}Y"oq
--重建索引 U.~G{H`G,u
DBCC REINDEX s
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DBCC INDEXDEFRAG s=jH1^
--收缩数据和日志 MmvJ)|&t
DBCC SHRINKDB 4l*cX1!
DBCC SHRINKFILE o@360#njF
3、压缩数据库 %$ o[,13=
dbcc shrinkdatabase(dbname) = )3\B
4、转移数据库给新用户以已存在用户权限 #U%HGTE0
exec sp_change_users_login 'update_one','newname','oldname' .kuNn-$
go ALF21e*n
5、检查备份集 N&
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' EMr|#}]#s
6、修复数据库 1@'I eywg
ALTER DATABASE [dvbbs] SET SINGLE_USER {#?|&n<
GO +(:Qf+:
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK (:E@kpK
GO b#6mUl2
ALTER DATABASE [dvbbs] SET MULTI_USER ;J+iwS*Z
GO s Adb0 A
7、日志清除 }8}`A\dgV
SET NOCOUNT ON J^#g?RHN>m
DECLARE @LogicalFileName sysname, \DE,
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@MaxMinutes INT, C"5P7F{
@NewSize INT ;?iu@h
USE tablename -- 要操作的数据库名 ]CcRI|g}
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 _\k?uUo&,^
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ;!
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@NewSize = 1 -- 你想设定的日志文件的大小(M) 85dC6wI4K
-- Setup / initialize Q
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DECLARE @OriginalSize int f &NX~(
SELECT @OriginalSize = size X)RgXl{
FROM sysfiles 5K?/-0yG
WHERE name = @LogicalFileName IOxtuR
SELECT 'Original Size of ' + db_name() + ' LOG is ' + "S'Yn-
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + (m Yi
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' *rxYal4ad
FROM sysfiles $u, 6x~>
WHERE name = @LogicalFileName qk^/&j
CREATE TABLE DummyTrans |/xA5_-N
(DummyColumn char (8000) not null) ~};q/-[r
DECLARE @Counter INT, WY@g=W>+
@StartTime DATETIME, YSPUQ
@TruncLog VARCHAR(255) *wJz0ex7R/
SELECT @StartTime = GETDATE(), l-c:'n
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' vc3r [mT
DBCC SHRINKFILE (@LogicalFileName, @NewSize) & uwOyb
EXEC (@TruncLog) VR"le&'z"
-- Wrap the log if necessary. \X(*JNQ
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired K@[Hej6d
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) T?A3f]U
AND (@OriginalSize * 8 /1024) > @NewSize aYk: CYQ
BEGIN -- Outer loop. A+H8\ew2,
SELECT @Counter = 0 l\N2C4NG
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) E%8uQ2p(
BEGIN -- update qo\9,<
INSERT DummyTrans VALUES ('Fill Log') eG2'W
DELETE DummyTrans s 8K.A~5 w
SELECT @Counter = @Counter + 1 '/loJz 1
END Au)~"N~p?
EXEC (@TruncLog) jFKp~`/#
END (#85<|z
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 6Xo "?f
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + m-~3c]pA
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' cotySio$
FROM sysfiles ppLLX1S
WHERE name = @LogicalFileName M?P\ YAn$
DROP TABLE DummyTrans lJfk4 -;M
SET NOCOUNT OFF *a8 <cf
8、说明:更改某个表 iYYuZ.
exec sp_changeobjectowner 'tablename','dbo' ,1CmB@
9、存储更改全部表 b$nev[`{6
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch SQ+r'g
@OldOwner as NVARCHAR(128), $g VbeQ
@NewOwner as NVARCHAR(128) >;j&]]-&
AS W79.Nj2`
DECLARE @Name as NVARCHAR(128) |${ImP
DECLARE @Owner as NVARCHAR(128) `?l
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DECLARE @OwnerName as NVARCHAR(128) yXEI%2~)
DECLARE curObject CURSOR FOR UYy #DA
select 'Name' = name, .dxELSV
'Owner' = user_name(uid) {gu3KV
from sysobjects |}YxxeAk
where user_name(uid)=@OldOwner ;{R;lF,
order by name jHHCJOHB8
OPEN curObject O+<+yQl
FETCH NEXT FROM curObject INTO @Name, @Owner Ke:EL;*8k
WHILE(@@FETCH_STATUS=0) qvWi;
BEGIN eYkg4 O'
if @Owner=@OldOwner Pq{p\Qkj
begin _e8v12s
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Hc|cA(9sh9
exec sp_changeobjectowner @OwnerName, @NewOwner x2HISxg
end PMbq5
-- select @name,@NewOwner,@OldOwner %Q}(.h%M
FETCH NEXT FROM curObject INTO @Name, @Owner D-i, C~W
END 6'uCwAQU
close curObject X$Q.A^9
deallocate curObject b-<@3N.9]
GO 726UO#*
10、SQL SERVER中直接循环写入数据 3PLA*n+%
declare @i int WLVkrTvX
set @i=1 8a8D0}'
while @i<30 Ie _{P&J
begin rhaq!s38:
insert into test (userid) values(@i) P&[&Dj
set @i=@i+1 )ryP K"V
end %8Y+Df;ax
小记存储过程中经常用到的本周,本月,本年函数 CHO_3QIz
Dateadd(wk,datediff(wk,0,getdate()),-1) >@?mP$;=
Dateadd(wk,datediff(wk,0,getdate()),6) ~g#/q~UE
Dateadd(mm,datediff(mm,0,getdate()),0) suWO:]FR
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) fY78
Dateadd(yy,datediff(yy,0,getdate()),0) %FqQ+0^
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) a
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上面的SQL代码只是一个时间段
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Dateadd(wk,datediff(wk,0,getdate()),-1) &~B8~U4%
Dateadd(wk,datediff(wk,0,getdate()),6) Ii/{xVMD
就是表示本周时间段. -h
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下面的SQL的条件部分,就是查询时间段在本周范围内的: \4<|QE
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) rp1+K4]P
而在存储过程中 =;I+:K
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) #bG6+"g{=L
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) {0/2Hw n