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。 cdDMV%V
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一、基础 fC2
1、说明:创建数据库 \k=.w
CREATE DATABASE database-name &~u=vuX
2、说明:删除数据库 [3s p
drop database dbname vu%:0p`K
3、说明:备份sql server yW$ja|^E
--- 创建 备份数据的 device pX:FXzYQ
USE master fC_dSM[{c
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ;JcOm&d/hk
--- 开始 备份 w2:!yQk_
BACKUP DATABASE pubs TO testBack 2o`a^'Iw
4、说明:创建新表 5!55v
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) \;?=h
根据已有的表创建新表: H(^O{JC]y!
A:create table tab_new like tab_old (使用旧表创建新表) gDw:Z/1X`
B:create table tab_new as select col1,col2... from tab_old definition only OAc*W<Q0
5、说明:删除新表 1$q>\
drop table tabname u7=jtB
6、说明:增加一个列 VK*2`Z1
Alter table tabname add column col type H:X=v+W
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。 'JBf*p".
7、说明:添加主键: Alter table tabname add primary key(col) FTy`#*7Ul
说明:删除主键: Alter table tabname drop primary key(col) x9#>0
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8、说明:创建索引:create [unique] index idxname on tabname(col....) +$#YW5wy
删除索引:drop index idxname '8NKrI
注:索引是不可更改的,想更改必须删除重新建。 1@nGD<,.
9、说明:创建视图:create view viewname as select statement %`%xD>![
删除视图:drop view viewname _jw A_
10、说明:几个简单的基本的sql语句 kF9T 9
选择:select * from table1 where 范围 ,KlTitJl\+
插入:insert into table1(field1,field2) values(value1,value2) |5wuYG
删除:delete from table1 where 范围 yJaQcGxE"
更新:update table1 set field1=value1 where 范围 g<[_h(xDeG
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! zX-6]j;
排序:select * from table1 order by field1,field2 [desc] a2dlz@)J
总数:select count as totalcount from table1 T,72I
求和:select sum(field1) as sumvalue from table1 ~-,P1u!
平均:select avg(field1) as avgvalue from table1 +e0]Y8J{
最大:select max(field1) as maxvalue from table1 !*:Zcg?7n
最小:select min(field1) as minvalue from table1 u"K-mr#$[o
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11、说明:几个高级查询运算词 `x"0
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A: UNION 运算符 \o^M ,yI
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。 eH2.,wY1
B: EXCEPT 运算符 %d+:0.+`n
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。 IBx?MU#.
C: INTERSECT 运算符 +igFIoHTM
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。 td@F%*
注:使用运算词的几个查询结果行必须是一致的。 R>"E Xq
12、说明:使用外连接 "
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A、left outer join: E'=~<&
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;FA@g(g
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 .`!|^h%0
B:right outer join: &0O1tM*v
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。 5Qp5JMK
C:full outer join: b|T}mn
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_%;O5
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二、提升 x. r~e)x=
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) im^G{3z
法一:select * into b from a where 1<>1 m :ROq
法二:select top 0 * into b from a M:W9h+z
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) t_&FK A
insert into b(a, b, c) select d,e,f from b; ;m}lmq,
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) da3]#%i0
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 $4`RJ{ZJw]
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. J<:qzwh
4、说明:子查询(表名1:a 表名2:b) *-bR~
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) [3s,U4a
5、说明:显示文章、提交人和最后回复时间 rMqWXGl`(
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b " *xQN "F
6、说明:外连接查询(表名1:a 表名2:b) /sENoQR
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 7-+X -Y?
7、说明:在线视图查询(表名1:a ) M'D;2qo
select * from (SELECT a,b,c FROM a) T where t.a > 1; c"%XE#D
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 B`a5%asJn
select * from table1 where time between time1 and time2 w
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select a,b,c, from table1 where a not between 数值1 and 数值2 7ZHM;_
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9、说明:in 的使用方法
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select * from table1 where a [not] in ('值1','值2','值4','值6') $kJvPwRO
10、说明:两张关联表,删除主表中已经在副表中没有的信息 GLA,,i'i9
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) !3K6ew>Sf
11、说明:四表联查问题: OqDLb
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... mq~7v1kw
12、说明:日程安排提前五分钟提醒 u >H^bCXI
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 De[!^/f;T
13、说明:一条sql 语句搞定数据库分页 y";{k+
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 pi? q<p%
14、说明:前10条记录 8^ ;[c
select top 10 * form table1 where 范围 )`Tny]M
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) .:c^G[CQ^9
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 7|3Z+#|T
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 ):eX*
(select a from tableA ) except (select a from tableB) except (select a from tableC) *&>1A A
17、说明:随机取出10条数据 St/Hv[H'[E
select top 10 * from tablename order by newid() Oh<[8S7]C
18、说明:随机选择记录 RNuOwZ1m
select newid() .l5y!?
19、说明:删除重复记录 %"j<`
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) lyKV^7}
20、说明:列出数据库里所有的表名 Mw7 ~:O`
select name from sysobjects where type='U' GiB3.%R`
21、说明:列出表里的所有的 y}ez js
select name from syscolumns where id=object_id('TableName') E0}`+x
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 [i.2lt#]
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type
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显示结果: fR!'i):u
type vender pcs R{kZKD=
电脑 A 1 wQ[~7 ,o
电脑 A 1 `!5ZF@Q>e
光盘 B 2 Yd lXMddE
光盘 A 2 {Q^P<
手机 B 3 ]*U\ gm%
手机 C 3 D M{7x77
23、说明:初始化表table1 lu_ y 9o^
TRUNCATE TABLE table1 D0=D8P}H:
24、说明:选择从10到15的记录 K9}ppgL'$
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 2|(J<H
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三、技巧 /iNCb&[
1、1=1,1=2的使用,在SQL语句组合时用的较多 7Q} P}9n
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 0)-l9V
如: -DhF> 4f
if @strWhere !='' S0 M-$
begin ^]^Y~$u
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere X1!m]s(I
end dx}()i\@
else "jmi
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begin :x]gTZ?
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' +bI &0`
end -ZH]i}$
我们可以直接写成 3zY"9KUN
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ?s #DD,
2、收缩数据库 "P.7FD
--重建索引 {w}PV5<
DBCC REINDEX q
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DBCC INDEXDEFRAG [3;J,P=&
--收缩数据和日志 m!a<\0^
DBCC SHRINKDB %FLz}QW*
DBCC SHRINKFILE eI; %/6#
3、压缩数据库 8vz9o <I
dbcc shrinkdatabase(dbname) ~d?7\:n
4、转移数据库给新用户以已存在用户权限 `,tv&siSA
exec sp_change_users_login 'update_one','newname','oldname' #JeZA0r5
go }k7@
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5、检查备份集 soA>&b!?
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' K&<bn22
6、修复数据库 lyfLkBF
ALTER DATABASE [dvbbs] SET SINGLE_USER \06fP4?
GO }3j/%oN.(
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 1\{0z3P
GO 'wvZnb
ALTER DATABASE [dvbbs] SET MULTI_USER 1wuLw Ad
GO 1C^6'9o
7、日志清除 'CjcOI
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SET NOCOUNT ON ='T<jV`evu
DECLARE @LogicalFileName sysname, bw9a@X
@MaxMinutes INT, ;$&&tEh)
@NewSize INT ik_Ll|
USE tablename -- 要操作的数据库名 724E(?>J
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Vd4x!Vk
@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) 0!o&=Qh
-- Setup / initialize =B4mi.;@i
DECLARE @OriginalSize int Xl;u
SELECT @OriginalSize = size $TtCVR
FROM sysfiles N-]h+Cnyu
WHERE name = @LogicalFileName x&+/da-E/5
SELECT 'Original Size of ' + db_name() + ' LOG is ' + X8<<;?L
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + b)(#/}jMkD
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' @G^]kDFM{
FROM sysfiles
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WHERE name = @LogicalFileName {6~v oVkj
CREATE TABLE DummyTrans C^K?"800
(DummyColumn char (8000) not null) Q?L-6]pg
DECLARE @Counter INT, fxXZ^#2wX
@StartTime DATETIME, ^;$a_eR
@TruncLog VARCHAR(255) )MHvuk:I)
SELECT @StartTime = GETDATE(), /hOp>|
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 7ml,
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ? Sj,HLo@U
EXEC (@TruncLog) [m?eSq6e2b
-- Wrap the log if necessary. {[61LQ6V9
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired UMpC2)5
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) :R{Xd{?
AND (@OriginalSize * 8 /1024) > @NewSize HZ5*PXg~
BEGIN -- Outer loop. q El:2 <
SELECT @Counter = 0 X2(TuR*t
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) tk|Ew!M:
BEGIN -- update 0qnToV;
INSERT DummyTrans VALUES ('Fill Log') hvQOwA;e
DELETE DummyTrans \,!FL))yC
SELECT @Counter = @Counter + 1 29z+<?K{
END epJVs0W
EXEC (@TruncLog) K;,n?Q w
END +IK~a9t
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 7]@vPr;:
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + y'*^ '
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' b4Zkj2L
FROM sysfiles HY~\e|o
WHERE name = @LogicalFileName dMCV
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DROP TABLE DummyTrans b|u4h9
SET NOCOUNT OFF I{;s.2
8、说明:更改某个表 q62TYg}
exec sp_changeobjectowner 'tablename','dbo' 79n,bb5
9、存储更改全部表
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch =7e~L 3 K
@OldOwner as NVARCHAR(128), ={~`0,
@NewOwner as NVARCHAR(128) E[/<AY^@!z
AS UaiDo"i
DECLARE @Name as NVARCHAR(128) A 7'dD$9
DECLARE @Owner as NVARCHAR(128)
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DECLARE @OwnerName as NVARCHAR(128) D@rOX (m
DECLARE curObject CURSOR FOR IfF<8~~E
select 'Name' = name, Z=|:D,&
'Owner' = user_name(uid) S)C =Q~&
from sysobjects QY8I_VF
where user_name(uid)=@OldOwner CtTG`)"|
order by name 'M=(5p
OPEN curObject <,(6*b
FETCH NEXT FROM curObject INTO @Name, @Owner AmM^&
WHILE(@@FETCH_STATUS=0) Nj1vB;4Nx
BEGIN -A(]",*J
if @Owner=@OldOwner "(F>?pq
begin yd]W',c
set @OwnerName = @OldOwner + '.' + rtrim(@Name) R;.zS^LL
exec sp_changeobjectowner @OwnerName, @NewOwner sEt5!&