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。 Y6H?ZOq
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一、基础 9T5 F0?qd
1、说明:创建数据库 K Cw
CREATE DATABASE database-name *AW v
2、说明:删除数据库 fW+"Kuw
drop database dbname ^uN[rHZ*u
3、说明:备份sql server a{Y|`*7y
--- 创建 备份数据的 device 3en67l
USE master ~mXzQbe
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' d~%7A5
--- 开始 备份 U&u6356
BACKUP DATABASE pubs TO testBack VrP{U-`
4、说明:创建新表 T1.U (::
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) <nD@4J-A0
根据已有的表创建新表: [~
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A:create table tab_new like tab_old (使用旧表创建新表) :??W3ROn
B:create table tab_new as select col1,col2... from tab_old definition only #&?ER]|3
5、说明:删除新表 -d#08\
drop table tabname [r8[lkR
6、说明:增加一个列 7<MEM NYX
Alter table tabname add column col type d94k
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。 D:bmq93PC
7、说明:添加主键: Alter table tabname add primary key(col) gDLS)4^w
说明:删除主键: Alter table tabname drop primary key(col) EJTM
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8、说明:创建索引:create [unique] index idxname on tabname(col....) O!f37n-TB
删除索引:drop index idxname 4c 8{AZ
注:索引是不可更改的,想更改必须删除重新建。 l1'v`!
9、说明:创建视图:create view viewname as select statement RH<2f5-sC!
删除视图:drop view viewname M.}J SDt
10、说明:几个简单的基本的sql语句 kBcTXl
选择:select * from table1 where 范围 rDbtT*vN
插入:insert into table1(field1,field2) values(value1,value2) JG'%HJ"D
删除:delete from table1 where 范围 1uj~/M
更新:update table1 set field1=value1 where 范围 d]O:VghY\
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! v+ in:\Dv
排序:select * from table1 order by field1,field2 [desc] gMF6f%
总数:select count as totalcount from table1 7:pc%Ksq
求和:select sum(field1) as sumvalue from table1 ;5[OS8
平均:select avg(field1) as avgvalue from table1 F%o!+%&7
最大:select max(field1) as maxvalue from table1 |TMn
最小:select min(field1) as minvalue from table1 R@jMFh;
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11、说明:几个高级查询运算词 vu^mLc
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A: UNION 运算符 oj Y.6w
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。 ~nmFZ]y
B: EXCEPT 运算符 X5/fy"g&
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。 6[ 3 K@
C: INTERSECT 运算符 "q M
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。 i56Rdb
注:使用运算词的几个查询结果行必须是一致的。 FsWp>}o
12、说明:使用外连接 ph6'(,
A、left outer join: G6a 2]
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。 /96lvn]8lO
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 dV
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B:right outer join: \u[}
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。 7AT8QC`u
C:full outer join: }#ta3 x
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。 [.xY>\e
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二、提升 Qe_{<E
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) >xS({1A}
法一:select * into b from a where 1<>1 nfHjIYid
法二:select top 0 * into b from a bk<Rp84vL
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) bH/4f93Nb
insert into b(a, b, c) select d,e,f from b; =-:%~ng
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) u3O@ccJ;
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 mih}?oi
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. KqJln)7
4、说明:子查询(表名1:a 表名2:b) Lr:n
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) B//*hH >F
5、说明:显示文章、提交人和最后回复时间 -+1O*L!
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b )SJM:E
6、说明:外连接查询(表名1:a 表名2:b) 3 5.&!4}
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ( `bb1gz
7、说明:在线视图查询(表名1:a ) $%DoLpE>
select * from (SELECT a,b,c FROM a) T where t.a > 1; N ~=PecQ
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 )GVTa4}p
select * from table1 where time between time1 and time2 -F `GZ
select a,b,c, from table1 where a not between 数值1 and 数值2 2yn"K|
9、说明:in 的使用方法 |\uj(|
select * from table1 where a [not] in ('值1','值2','值4','值6') <dP\vLH_
10、说明:两张关联表,删除主表中已经在副表中没有的信息 i;C` .+
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) )4B`U(%M~
11、说明:四表联查问题: zX*5yNd
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... OXQA(%MK
12、说明:日程安排提前五分钟提醒 }B7Txo,Z
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ux1(>
13、说明:一条sql 语句搞定数据库分页 h'&<A_C-7
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 ~%=%5}
14、说明:前10条记录 "y"oV[`
select top 10 * form table1 where 范围 &Hp*A^M
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) (c)/&~aE
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) jXf@JxQ
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 )e3w-es~4
(select a from tableA ) except (select a from tableB) except (select a from tableC) DmuQE~DV
17、说明:随机取出10条数据 LJ@(jO{z
select top 10 * from tablename order by newid() +`Q]p "G
18、说明:随机选择记录 vFdI?(c-
select newid() V':A!
19、说明:删除重复记录 @br)m](@
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) vb>F)po1}
20、说明:列出数据库里所有的表名 sS
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select name from sysobjects where type='U' W+Mw:,>*s
21、说明:列出表里的所有的 xS12$ib ~G
select name from syscolumns where id=object_id('TableName') `K+%/|!
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。 su=MMr>
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 [06m{QJ)1
显示结果: Nkj$6(N=zJ
type vender pcs U"8Hw@
电脑 A 1 9Jh&C5\\
电脑 A 1 0~BaQ,
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光盘 B 2 E3j`e>Yz
光盘 A 2 ?sdSi--
手机 B 3 %!A:Ka!m.
手机 C 3 t27UlFX
23、说明:初始化表table1 ck0%H#BYY
TRUNCATE TABLE table1 D1-/#QN$1
24、说明:选择从10到15的记录 akr2Os
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc L:Rg3eo
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三、技巧 7Ji'7$
1、1=1,1=2的使用,在SQL语句组合时用的较多 )C?H m^#
"where 1=1" 是表示选择全部 "where 1=2"全部不选, a+lNXlh=
如: %$zak@3%'
if @strWhere !='' ;5X~"#%U_
begin ({Md({|
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere \jk*Nm8;
end _ s}aF
else NbU4|Oi
begin t^MTR6y+8
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' &aIFtlC
end }G{"Mp4
我们可以直接写成 Rq+7&%dy
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere _GxC|d
2、收缩数据库 w=_^n]`R
--重建索引
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DBCC REINDEX `+< ^Svou
DBCC INDEXDEFRAG >2>/
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--收缩数据和日志 HN`qMGW^
DBCC SHRINKDB q%d'pF
DBCC SHRINKFILE ?m~1b_@A{
3、压缩数据库 08jk~$%
dbcc shrinkdatabase(dbname) u
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4、转移数据库给新用户以已存在用户权限 g$e|y#Ic$
exec sp_change_users_login 'update_one','newname','oldname' }U'9 d#N
go 9a=:e=q3#
5、检查备份集 =gSc{ i|
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' VOr:G85*s
6、修复数据库 6;Z`9PGp
ALTER DATABASE [dvbbs] SET SINGLE_USER d:>^]5cE&
GO U5j4iz'
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK FYFlh^}
GO )=gU~UV
ALTER DATABASE [dvbbs] SET MULTI_USER H0OO+MCe
GO -?#iPvk6
7、日志清除 IfB .2e`
SET NOCOUNT ON Z}0{FwW"4
DECLARE @LogicalFileName sysname, M .6BFC
@MaxMinutes INT, qZ>_{b0f
@NewSize INT -!7Z
USE tablename -- 要操作的数据库名 HTiLA%%6
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 {9 |*au(K
@MaxMinutes = 10, -- Limit on time allowed to wrap log. d`V.i6u
@NewSize = 1 -- 你想设定的日志文件的大小(M) MXl_{8
-- Setup / initialize fCNQUK{Gs5
DECLARE @OriginalSize int e}{#VB<
SELECT @OriginalSize = size *^;
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FROM sysfiles M {'(+a[
WHERE name = @LogicalFileName ?;UR9f|!
SELECT 'Original Size of ' + db_name() + ' LOG is ' + QhRz57'
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + gzhIOeY
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' aO}hE2]
FROM sysfiles <L8FI78[*
WHERE name = @LogicalFileName i75\<X
CREATE TABLE DummyTrans ]Kjt@F";
(DummyColumn char (8000) not null) 8dx7@y?z
DECLARE @Counter INT, 7wW x 8
@StartTime DATETIME, 5V(#nz
@TruncLog VARCHAR(255) dKEy6C"@
SELECT @StartTime = GETDATE(), <f:(nGj
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' -J6`
DBCC SHRINKFILE (@LogicalFileName, @NewSize) V[%IU'{:
EXEC (@TruncLog) 6`'g ${U
-- Wrap the log if necessary. yph@H!@
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired aJ=)5%$6kc
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) q0ab]g+
AND (@OriginalSize * 8 /1024) > @NewSize l v:GiA"X
BEGIN -- Outer loop. 0@{bpc rc
SELECT @Counter = 0
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 4w9=z,
BEGIN -- update d5L BL'/o
INSERT DummyTrans VALUES ('Fill Log') !.# g
DELETE DummyTrans ]vR
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SELECT @Counter = @Counter + 1 ex~"M&^
END }U>K>"AZl
EXEC (@TruncLog) }@
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END ;s$4/b/~
SELECT 'Final Size of ' + db_name() + ' LOG is ' + D0bpD
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ]Q.S Is
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Sru0j/|H\
FROM sysfiles *^{j!U37s
WHERE name = @LogicalFileName ,if~%'9j
DROP TABLE DummyTrans F
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SET NOCOUNT OFF
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8、说明:更改某个表 CTg79
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exec sp_changeobjectowner 'tablename','dbo' l{3zlXk3z
9、存储更改全部表 n?6^j8i
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch _?felxG[
@OldOwner as NVARCHAR(128), !Y|xu07
@NewOwner as NVARCHAR(128) )R<93`q
AS ,@p4HN*
DECLARE @Name as NVARCHAR(128) 7~1Fy{tc
DECLARE @Owner as NVARCHAR(128) CaED(0
DECLARE @OwnerName as NVARCHAR(128) R86i2',
DECLARE curObject CURSOR FOR nt&%
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select 'Name' = name, ^FNju/b
'Owner' = user_name(uid) yRQ1Szbjli
from sysobjects qh}+b^Wi
where user_name(uid)=@OldOwner =v?V
order by name YwH Fn+
OPEN curObject O+'k4
FETCH NEXT FROM curObject INTO @Name, @Owner @JdeOL;
WHILE(@@FETCH_STATUS=0) 3:$@DZT$
BEGIN %kkDitmI{
if @Owner=@OldOwner r&v!2A]:
begin <x<qO=lq
set @OwnerName = @OldOwner + '.' + rtrim(@Name) J<"Z6 '0v
exec sp_changeobjectowner @OwnerName, @NewOwner &a\w+
end &'/PEOu&}G
-- select @name,@NewOwner,@OldOwner 3zfiegY@wm
FETCH NEXT FROM curObject INTO @Name, @Owner ~3Qa-s;g
END leSBR,C
close curObject *h?}~!AjY
deallocate curObject cRag0.[
GO s^)(.e_
10、SQL SERVER中直接循环写入数据 "IJ1b~j?
declare @i int N1y,~Z
set @i=1 I
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while @i<30 Ai 8+U)
begin _a$5"
insert into test (userid) values(@i) 07(LLhk@d
set @i=@i+1 {9P(U\]e]k
end $Sm iN'7;
小记存储过程中经常用到的本周,本月,本年函数 ~k@{b&
Dateadd(wk,datediff(wk,0,getdate()),-1) u@Ni *)p`
Dateadd(wk,datediff(wk,0,getdate()),6) ZV5IZ&V!
Dateadd(mm,datediff(mm,0,getdate()),0)
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 1 Cz}|#U
Dateadd(yy,datediff(yy,0,getdate()),0) })mD{c/
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) WT,dTn;W
上面的SQL代码只是一个时间段 -zt*C&)b
Dateadd(wk,datediff(wk,0,getdate()),-1) Y nTx)uW
Dateadd(wk,datediff(wk,0,getdate()),6) J1M9),
就是表示本周时间段. cF9ZnT.
下面的SQL的条件部分,就是查询时间段在本周范围内的: 4},Y0 QXw
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) eA(FWO
而在存储过程中 y^X]q[-?
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 8c%N+E]
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) \G/ZA) t