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。 X*`b}^T
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一、基础 pbGv\SF
1、说明:创建数据库 tQ)l4Y 8
CREATE DATABASE database-name ;7(vqm<V2~
2、说明:删除数据库 wNMA)S
drop database dbname vg5fMH9ZZ
3、说明:备份sql server e4;h*IQK
--- 创建 备份数据的 device 07>D G#
USE master -~
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Q}1qt4xy*
--- 开始 备份 -#r=
BACKUP DATABASE pubs TO testBack 'K|F{K
4、说明:创建新表 SfPtG
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Gyc_B
根据已有的表创建新表: <,J O
A:create table tab_new like tab_old (使用旧表创建新表) u`pw'3hY
B:create table tab_new as select col1,col2... from tab_old definition only GYV%RD #
5、说明:删除新表 b[MKo7
drop table tabname B8>@q!G8P
6、说明:增加一个列 nE4rB\
Alter table tabname add column col type }'h\;8y
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,o|>e$
7、说明:添加主键: Alter table tabname add primary key(col) Us3zvpy)o
说明:删除主键: Alter table tabname drop primary key(col) .~|[*
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8、说明:创建索引:create [unique] index idxname on tabname(col....) ;bFd*8?;
删除索引:drop index idxname ~l*[=0}
注:索引是不可更改的,想更改必须删除重新建。 QfL8@W~e
9、说明:创建视图:create view viewname as select statement @QDpw1;V'
删除视图:drop view viewname tZ:fh p
10、说明:几个简单的基本的sql语句 DN;$->>
选择:select * from table1 where 范围 9+~1# |
插入:insert into table1(field1,field2) values(value1,value2) n%6=w9.%c
删除:delete from table1 where 范围 a4",BDx
更新:update table1 set field1=value1 where 范围 <SRo2rjRa
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! @`aPr26>?
排序:select * from table1 order by field1,field2 [desc] |pE
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总数:select count as totalcount from table1 PrF('PH7i
求和:select sum(field1) as sumvalue from table1 3lgD,_&
平均:select avg(field1) as avgvalue from table1 #_zj5B38E
最大:select max(field1) as maxvalue from table1 jIWX6
最小:select min(field1) as minvalue from table1 T;3B_lu]
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11、说明:几个高级查询运算词 r<'B\.#tp>
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A: UNION 运算符 /km0[M
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。 LtK,_j
B: EXCEPT 运算符 7+rroCr"
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。 $^W|@et{
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C: INTERSECT 运算符 [V0%=q+ R
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 3C2~heO>|
注:使用运算词的几个查询结果行必须是一致的。 cd4HbSp
12、说明:使用外连接 X&!($*/
A、left outer join: DOq"=R+
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。 ?Xqkf>
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/u<`)
B:right outer join: cgR8+o
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。 t]xR`Rr;X
C:full outer join: z/i&Lpr:
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。 }L>0}H
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二、提升 IC-W[~
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) cq8JpSB(
法一:select * into b from a where 1<>1 kM3#[#6$!
法二:select top 0 * into b from a _"82W^W i
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Nk?/vMaw
insert into b(a, b, c) select d,e,f from b; ]F"@+_E
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) v5*JBW+c*
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 2D"aAI<P
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 8>(/:u_x
4、说明:子查询(表名1:a 表名2:b) aF.fd2k
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) I %CrsEo
5、说明:显示文章、提交人和最后回复时间 au/5`
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b H~W=#Cx
6、说明:外连接查询(表名1:a 表名2:b) GsIqUM#R
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c JY$;m3h
7、说明:在线视图查询(表名1:a ) JC7:0A^
select * from (SELECT a,b,c FROM a) T where t.a > 1; H)5" <=]
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 ?F|F~A8dr
select * from table1 where time between time1 and time2 5zH_yZ@+
select a,b,c, from table1 where a not between 数值1 and 数值2 Om2w+yU
9、说明:in 的使用方法 66scBi_d
select * from table1 where a [not] in ('值1','值2','值4','值6') O?iLLfs
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ;V84Dy#b
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) e,l-}=5*P
11、说明:四表联查问题: i_p-|I:hQ
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 ..... KuMH,rXF
12、说明:日程安排提前五分钟提醒 n{"a0O
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 U Fyk%#L
13、说明:一条sql 语句搞定数据库分页 Oki{)Ssy
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 "fu@2y4^
14、说明:前10条记录 *4c5b'u
select top 10 * form table1 where 范围 I~,b ZA
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.) TmJXkR.5
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) fj[Kbo 7!h
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 [!`5kI
(select a from tableA ) except (select a from tableB) except (select a from tableC) Zl?9ibm;@
17、说明:随机取出10条数据 ,
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select top 10 * from tablename order by newid() kk}_AZ0eK
18、说明:随机选择记录 A1B%<$|pz
select newid() E|_}?>{R
19、说明:删除重复记录 k!d<2Qp W
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) `{Fz
20、说明:列出数据库里所有的表名 igF<].'V
select name from sysobjects where type='U' 0*6Q8`I
21、说明:列出表里的所有的 FPu$N d&\
select name from syscolumns where id=object_id('TableName') Tj!rAMQk
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。 A&X
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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 8*&YQId~
显示结果: ,Eo\(j2F.
type vender pcs (SByN7[gb
电脑 A 1 J#\oc@
电脑 A 1 W4)bEWO+q
光盘 B 2 _ U Y5
光盘 A 2 cuL/y$+EY
手机 B 3 u"DE?
手机 C 3 CM)V^k*
23、说明:初始化表table1 <>V~
TRUNCATE TABLE table1 Ka$lNL3<j
24、说明:选择从10到15的记录 >C`#4e?}
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc xggF:El3{
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三、技巧 c~!ETwpHQ
1、1=1,1=2的使用,在SQL语句组合时用的较多 V9wL3*
"where 1=1" 是表示选择全部 "where 1=2"全部不选, %{0F.
如: 'Qg.D88
if @strWhere !='' 8(
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begin dEam|
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere %I@vM s^
end d"thM
else nY,LQ0r
begin m,ur{B8 :
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' o 80x@ &A:
end AsI.8"
我们可以直接写成 JI/iq
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere uYijzHQyD
2、收缩数据库 3!i{4/
--重建索引 {"db1Gbfg
DBCC REINDEX '30JJ0
DBCC INDEXDEFRAG w^}*<q\
--收缩数据和日志 2%)~E50U
DBCC SHRINKDB chM-YuN|
DBCC SHRINKFILE gOy{ RE
3、压缩数据库 BJ{?S{"6%G
dbcc shrinkdatabase(dbname) oslj<
4、转移数据库给新用户以已存在用户权限 N:,V{Pw
exec sp_change_users_login 'update_one','newname','oldname' 3A\Z]L
go UI*&@!%bzp
5、检查备份集 {a(<E8-^
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ..=lM:13|
6、修复数据库 'h[7AZ&)#
ALTER DATABASE [dvbbs] SET SINGLE_USER Mo4c8wp&SM
GO @2TfW]6
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ;s#]."v_=
GO (N5"'`NZA
ALTER DATABASE [dvbbs] SET MULTI_USER V6'k\5| _
GO ^1Bk*?Yx\x
7、日志清除 y (=0
SET NOCOUNT ON |7!B k$(vA
DECLARE @LogicalFileName sysname, )))AxgM
@MaxMinutes INT, ?',Wn3A
@NewSize INT X7?j90tH
USE tablename -- 要操作的数据库名 TV}=$\D
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ^=qV)j
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Omph(
@NewSize = 1 -- 你想设定的日志文件的大小(M) ri4:w_/{,Y
-- Setup / initialize qJR8fQ
DECLARE @OriginalSize int ] ~}~d(
SELECT @OriginalSize = size EF;B)y=
FROM sysfiles .ZM0cwF
WHERE name = @LogicalFileName S(lqj6aa}
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ""h%RhcZ\
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + qBZ;S3
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' JvS
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FROM sysfiles KVoM\ttP
WHERE name = @LogicalFileName AOx8OiqE:
CREATE TABLE DummyTrans TJuS)AZ
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(DummyColumn char (8000) not null) /mwDVP<z /
DECLARE @Counter INT, S5~(3I
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@StartTime DATETIME, a~zh5==QD
@TruncLog VARCHAR(255) D3y4e8+Z'
SELECT @StartTime = GETDATE(), MI~QXy,
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' %h
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) R9UC0D:-x
EXEC (@TruncLog) V=c?V/pl
-- Wrap the log if necessary. m~F ~9&
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 0\+$j5;
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ac8su0
AND (@OriginalSize * 8 /1024) > @NewSize )4H0Bz2G
BEGIN -- Outer loop. lE3&8~2
SELECT @Counter = 0 7r pTk&`
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) sR| /s3;
BEGIN -- update 7>-99o^W
INSERT DummyTrans VALUES ('Fill Log') l
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DELETE DummyTrans 6L2Wv5C
SELECT @Counter = @Counter + 1 E&Sr+D aPD
END m*v@L4t(1
EXEC (@TruncLog) VYrs4IFT$
END A$?o3--#]G
SELECT 'Final Size of ' + db_name() + ' LOG is ' + n% s$!R-\
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 2(R{3E4.
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' \3)U~[O>:
FROM sysfiles <iM}p^jX9
WHERE name = @LogicalFileName T%**:@}+
DROP TABLE DummyTrans \p )eY#A
SET NOCOUNT OFF h{ eQ\iI
8、说明:更改某个表 GD!!xt
exec sp_changeobjectowner 'tablename','dbo' |xpOU*k
9、存储更改全部表 " pL5j
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch u3HaWf3
@OldOwner as NVARCHAR(128), +\J+?jOC4S
@NewOwner as NVARCHAR(128) 0- u,AD
AS CC]q\%y-_
DECLARE @Name as NVARCHAR(128) #?~G\Ux0/
DECLARE @Owner as NVARCHAR(128) ,Uy~O(Ft
DECLARE @OwnerName as NVARCHAR(128) Po.izE!C
DECLARE curObject CURSOR FOR zhU^~4F
select 'Name' = name, g5
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'Owner' = user_name(uid) ^;@!\Rc
from sysobjects =E&1e;_xlE
where user_name(uid)=@OldOwner e(9K.3@{
order by name e{.P2rnh
OPEN curObject ~~#/jULbV
FETCH NEXT FROM curObject INTO @Name, @Owner > Qh#pn*
WHILE(@@FETCH_STATUS=0) ZV[-$
BEGIN r1sA^2g.
if @Owner=@OldOwner XL(2Qk
begin tz2$j@!=
set @OwnerName = @OldOwner + '.' + rtrim(@Name) /q^_
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exec sp_changeobjectowner @OwnerName, @NewOwner h\8bo=
end j)}TZx4~
-- select @name,@NewOwner,@OldOwner :{?Pq8jP
FETCH NEXT FROM curObject INTO @Name, @Owner ' &Nv|v\V
END $ccCI
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close curObject +sXnC\
deallocate curObject 07Oagq(
GO ]jV1/vJ-!
10、SQL SERVER中直接循环写入数据 ) 3I|6iS
declare @i int YV6w}b:
set @i=1 P}-S[[b73s
while @i<30 :Y)G- :S+
begin 3;Tsjv}
insert into test (userid) values(@i) 3.%jet1
set @i=@i+1 PH!rWR
end wT:mfS09N
小记存储过程中经常用到的本周,本月,本年函数 yI's=Iu`
Dateadd(wk,datediff(wk,0,getdate()),-1) l+?sR<e?!
Dateadd(wk,datediff(wk,0,getdate()),6) [8[`V)b
Dateadd(mm,datediff(mm,0,getdate()),0) fjS#
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ))J#t{X/8v
Dateadd(yy,datediff(yy,0,getdate()),0) ZMch2 U8
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 3UJSK+d\
上面的SQL代码只是一个时间段 ak(P<OC-
Dateadd(wk,datediff(wk,0,getdate()),-1) $oZV 54
Dateadd(wk,datediff(wk,0,getdate()),6) gn[h:+H&
就是表示本周时间段. N0fmC*1-
下面的SQL的条件部分,就是查询时间段在本周范围内的: r7v1q
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Ft8ii|-
而在存储过程中 ['l}*
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) dj3E20Ws
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) a<Ps6'