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。 .?rs5[th*
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一、基础 [u;(4sa}
1、说明:创建数据库 4CchE15
CREATE DATABASE database-name ;~DrsQb
2、说明:删除数据库 utRO?]%d
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drop database dbname ~Er0$+q=Y;
3、说明:备份sql server Q|P
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--- 创建 备份数据的 device rz,,ku4qt
USE master r>! @Z2%s
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' @67GVPcxl
--- 开始 备份 q+4dHS)x
BACKUP DATABASE pubs TO testBack ~CHcbEWk)W
4、说明:创建新表 Q!3-P
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ;hODzfNkS
根据已有的表创建新表: "=K3sk
A:create table tab_new like tab_old (使用旧表创建新表) pGD-K41O]
B:create table tab_new as select col1,col2... from tab_old definition only jl}!UG
5、说明:删除新表 `jR8RDD
drop table tabname 9{U@s
6、说明:增加一个列 *g
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Alter table tabname add column col type M@7U]X$g
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。 !~RK2d
7、说明:添加主键: Alter table tabname add primary key(col) wLiPkW
说明:删除主键: Alter table tabname drop primary key(col) _.R]K$U
8、说明:创建索引:create [unique] index idxname on tabname(col....) O-ENFA~E;v
删除索引:drop index idxname Nt_sV7zzb
注:索引是不可更改的,想更改必须删除重新建。 !<=(/4o&P
9、说明:创建视图:create view viewname as select statement gx^_bHh
删除视图:drop view viewname 6T+y m9
10、说明:几个简单的基本的sql语句 cAGM|%
选择:select * from table1 where 范围 ^`M%g2x
插入:insert into table1(field1,field2) values(value1,value2) 6HJsIeQ
删除:delete from table1 where 范围 Xjxa
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更新:update table1 set field1=value1 where 范围 !]}C!dXd
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! j@#RfVx
排序:select * from table1 order by field1,field2 [desc] t5_76'@cX
总数:select count as totalcount from table1 Z
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求和:select sum(field1) as sumvalue from table1 y${`W94
平均:select avg(field1) as avgvalue from table1 -hfkF+=U'
最大:select max(field1) as maxvalue from table1 suIYfjh
最小:select min(field1) as minvalue from table1 %scIZCrI~
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11、说明:几个高级查询运算词 r QNm2h
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A: UNION 运算符 ~N}Zr$D
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 4,W,E4 7
B: EXCEPT 运算符 x5xMr.vm
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 Pzd!"Gl9
C: INTERSECT 运算符 rNicg]:\x
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 /=l!F'
注:使用运算词的几个查询结果行必须是一致的。 l&e{GHz
12、说明:使用外连接 ^\ln8!;
A、left outer join: -DJ,<f*$
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。 T`j{2
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 M6quPj
B:right outer join: u\iKdL
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。 0~_I9|FN
C:full outer join: c;]^aaQ+>
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。 !mWm@}Ujg
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二、提升 |;(P+Q4lB
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) _,v?rFLE
法一:select * into b from a where 1<>1 pRxVsOb
法二:select top 0 * into b from a q^6#.}
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) A7XA?>~+|
insert into b(a, b, c) select d,e,f from b; -G? IXgG
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) 1ljcbD)T;
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ?G7*^y&Q
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. z19%!k
4、说明:子查询(表名1:a 表名2:b) {,6J*v"o
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) @].!}tz
5、说明:显示文章、提交人和最后回复时间 E@)'Z6r1
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b "X!1^)W-8
6、说明:外连接查询(表名1:a 表名2:b) FqGMHM\J
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Y%y
7、说明:在线视图查询(表名1:a ) [ g:cG
select * from (SELECT a,b,c FROM a) T where t.a > 1; 0 |?N
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 1 |)CQ
select * from table1 where time between time1 and time2 =+?OsH
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select a,b,c, from table1 where a not between 数值1 and 数值2 EB}~^ aY
9、说明:in 的使用方法 9C Ki$L
select * from table1 where a [not] in ('值1','值2','值4','值6') 9M 1DE
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ,afO\oe>MG
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 8yDsl
11、说明:四表联查问题: [h&s<<#
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select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... _*{Lha
12、说明:日程安排提前五分钟提醒 jLO$[c`;
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 w@6y.v1I{
13、说明:一条sql 语句搞定数据库分页 $\1M"a}F
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 XhWo~zh"
14、说明:前10条记录 Pf?&ys6
select top 10 * form table1 where 范围 Z!fbc#L6
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.) iPG:w+G
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ]mNsG0r6
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 qkp0' f*}
(select a from tableA ) except (select a from tableB) except (select a from tableC) SD8>,
17、说明:随机取出10条数据 TXV^f*
select top 10 * from tablename order by newid() `)KGajB
18、说明:随机选择记录 p15dbr1
select newid() Rg46V-"d,@
19、说明:删除重复记录 XN?my@_HpM
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) QuI!`/N)z
20、说明:列出数据库里所有的表名 }y J,&N'p
select name from sysobjects where type='U' Bf+~&I#E
21、说明:列出表里的所有的 1P'L<z
select name from syscolumns where id=object_id('TableName') $[Nf?`f(t_
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。 g`.H)36
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 +7
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显示结果: hPGDN\#LD
type vender pcs iyUnxqP
电脑 A 1 JX&%5sn(
电脑 A 1 Buq(L6P9r
光盘 B 2 i& %dwqp
光盘 A 2 u WdKG({][
手机 B 3 H.]<fvP
手机 C 3 -?{g{6
23、说明:初始化表table1 $3ZQ|X[|+
TRUNCATE TABLE table1 1~2+w]-kU
24、说明:选择从10到15的记录 5
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc a0B%x!y^
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三、技巧 0HbCT3g.
1、1=1,1=2的使用,在SQL语句组合时用的较多 yOXEP
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Ytqx0
如: Hl{ul'o
if @strWhere !='' *&h]PhY
begin ft0d5n!ui4
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere !mwMSkkq
end b`DPlQHj
else )u]=^
begin ZdPqU\G^q
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' _ogN
end %X%f0J
我们可以直接写成 )7P>Hj
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere *g:Dg I 2
2、收缩数据库 Gb"kl.j
--重建索引 Y=<zR9f`
DBCC REINDEX z
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DBCC INDEXDEFRAG E0!0 uSg&
--收缩数据和日志 ]z=dRq
DBCC SHRINKDB YbZ?["S&
DBCC SHRINKFILE tF<&R&=
3、压缩数据库 Zm6jF
dbcc shrinkdatabase(dbname) W&I:z-VH
4、转移数据库给新用户以已存在用户权限 [L| vBr
exec sp_change_users_login 'update_one','newname','oldname' MA%g-}
go {S@,
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5、检查备份集 t)O]0)
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 3{ea~G)[9
6、修复数据库
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ALTER DATABASE [dvbbs] SET SINGLE_USER 8 QI+O`
GO SF ^$p$mC
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK NNJQDkO-I
GO j!0-3YKv
ALTER DATABASE [dvbbs] SET MULTI_USER or7l}X
GO W55kR.X6M
7、日志清除 1NrNTBI@
SET NOCOUNT ON KO[Ty'
DECLARE @LogicalFileName sysname, {8%KO1xB
@MaxMinutes INT, s~5rP:
@NewSize INT tpgD{BY^wJ
USE tablename -- 要操作的数据库名 fX1Ib$v
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 e%9zY{ABR%
@MaxMinutes = 10, -- Limit on time allowed to wrap log. AmCymT3P*e
@NewSize = 1 -- 你想设定的日志文件的大小(M) X@A8~kj1
-- Setup / initialize V9>$M=
DECLARE @OriginalSize int &=In
SELECT @OriginalSize = size PbV1FB_
FROM sysfiles Y%(8'Ch
WHERE name = @LogicalFileName usi3z9P>n
SELECT 'Original Size of ' + db_name() + ' LOG is ' + }%y5<n*v\
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ZlcEeG
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 1k$5'^]^9]
FROM sysfiles x4?g>v*J
WHERE name = @LogicalFileName C_h$$G{S(
CREATE TABLE DummyTrans \r3SvBwhFv
(DummyColumn char (8000) not null) <:StZ{o;
DECLARE @Counter INT, \34:]NM
@StartTime DATETIME, sv6m)pwh
@TruncLog VARCHAR(255) cCG!X%9
SELECT @StartTime = GETDATE(),
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 6_;n bqY&
DBCC SHRINKFILE (@LogicalFileName, @NewSize) [mG!-.ll
EXEC (@TruncLog) 5n e&6
-- Wrap the log if necessary. | `?J2WGe
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired @ykl:K%ke
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) @$~;vS
AND (@OriginalSize * 8 /1024) > @NewSize ~svea>Fmr
BEGIN -- Outer loop. ?ihRt+eR~
SELECT @Counter = 0 S++jwP
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) d^5x@E_Td
BEGIN -- update nM!_C-yX
INSERT DummyTrans VALUES ('Fill Log') 1>bNw-kz7
DELETE DummyTrans +h1X-K:I
SELECT @Counter = @Counter + 1 pMf
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END j:HIcCp
EXEC (@TruncLog) m:9|5W
END ;2aPhA
SELECT 'Final Size of ' + db_name() + ' LOG is ' + be(hY{y`
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + /%bnG(4
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' B~YOU3
FROM sysfiles /3;]e3x
WHERE name = @LogicalFileName !~xlze
DROP TABLE DummyTrans /.t1Ow
SET NOCOUNT OFF kJCeQK:W
8、说明:更改某个表 {=MRJg!U
exec sp_changeobjectowner 'tablename','dbo' b4(,ls
9、存储更改全部表 fBBtS S
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch g6OPYUPg
@OldOwner as NVARCHAR(128), 4(`U]dNcs
@NewOwner as NVARCHAR(128) %@HuAcNi
AS 7gRR/&ZK
DECLARE @Name as NVARCHAR(128) P9jSLM
DECLARE @Owner as NVARCHAR(128) qv<^%7gq
DECLARE @OwnerName as NVARCHAR(128) rG%8ugap
DECLARE curObject CURSOR FOR ZT<VDcP{
select 'Name' = name, ~sNBklK
'Owner' = user_name(uid) sH%Ts@Pl
from sysobjects tLP
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where user_name(uid)=@OldOwner _C,9c7K4
order by name `r %lB
OPEN curObject _9<Mo;C
FETCH NEXT FROM curObject INTO @Name, @Owner ehZ/J5
WHILE(@@FETCH_STATUS=0) vPrlRG6
BEGIN D8WKy
if @Owner=@OldOwner p&
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begin
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set @OwnerName = @OldOwner + '.' + rtrim(@Name)
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exec sp_changeobjectowner @OwnerName, @NewOwner ^W~8)Rbf
end VU+=b+B~m
-- select @name,@NewOwner,@OldOwner w8`B}Dr23
FETCH NEXT FROM curObject INTO @Name, @Owner jcRe),
END @qB>qD~WsD
close curObject G(bl)p^
deallocate curObject w,OPM}) il
GO PlwM3lrj
10、SQL SERVER中直接循环写入数据 R%`fd *g
declare @i int #6C<P!]V
set @i=1 u>*qDr*d
while @i<30 ONFx -U]
begin mRxeob
insert into test (userid) values(@i) ^,`]Q)P^
set @i=@i+1 4hkyq>c}
end 02-% B~oP
小记存储过程中经常用到的本周,本月,本年函数 n|B<rx?v
Dateadd(wk,datediff(wk,0,getdate()),-1) |*l^<= =
Dateadd(wk,datediff(wk,0,getdate()),6) ~m[Gp;pL
Dateadd(mm,datediff(mm,0,getdate()),0) 1yFIIj:^|
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) =o'g5Be<F
Dateadd(yy,datediff(yy,0,getdate()),0) BQ B<+o'
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Xi w
上面的SQL代码只是一个时间段 `$vf 9'\+
Dateadd(wk,datediff(wk,0,getdate()),-1) #] ;ulDq
Dateadd(wk,datediff(wk,0,getdate()),6) Af}o/g
就是表示本周时间段. |<uBJ-5
下面的SQL的条件部分,就是查询时间段在本周范围内的: g@Rs.Zq
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 7JBr{3;eS
而在存储过程中 v<mSd2B*
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) apnpy\in
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) #8y"1I=i&