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。 PCCE+wC6
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一、基础 Mx}r! Q
1、说明:创建数据库 ,$]m1|t@z
CREATE DATABASE database-name u9_?c
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2、说明:删除数据库 eI|FrBq%
drop database dbname uJ"#j
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3、说明:备份sql server ycN!N
--- 创建 备份数据的 device ~,W|i
USE master tT`S"
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' a aVq>$G3
--- 开始 备份 .WglLUJ:Z
BACKUP DATABASE pubs TO testBack L<
4、说明:创建新表 "P5,p"k:)
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) :Nz
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根据已有的表创建新表: `~axOp9N
A:create table tab_new like tab_old (使用旧表创建新表) @>`N%wH'
B:create table tab_new as select col1,col2... from tab_old definition only FkMM>X
5、说明:删除新表 J;fbE8x
drop table tabname 6T"5,Q</h
6、说明:增加一个列 FkaQVT
Alter table tabname add column col type <a
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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。 *4 m]UK
7、说明:添加主键: Alter table tabname add primary key(col) iLdUus!
说明:删除主键: Alter table tabname drop primary key(col) x+sSmW
8、说明:创建索引:create [unique] index idxname on tabname(col....) C
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删除索引:drop index idxname !rx5i
注:索引是不可更改的,想更改必须删除重新建。 nJH'^rO!C
9、说明:创建视图:create view viewname as select statement ;&b=>kPlZ
删除视图:drop view viewname 6/a%%1c1
10、说明:几个简单的基本的sql语句 KYhL}C+
选择:select * from table1 where 范围 o &b\bK%E
插入:insert into table1(field1,field2) values(value1,value2) k H06Cb
删除:delete from table1 where 范围 5G<`c
更新:update table1 set field1=value1 where 范围 *<9M|H~
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! SOD3MsAK
排序:select * from table1 order by field1,field2 [desc] $hM9{
总数:select count as totalcount from table1 Kd}%%L
求和:select sum(field1) as sumvalue from table1 .Sm 8t$
平均:select avg(field1) as avgvalue from table1 z#5qI',L
最大:select max(field1) as maxvalue from table1 rl"yE=
最小:select min(field1) as minvalue from table1 /0L]Pf;
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11、说明:几个高级查询运算词 m=`V
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A: UNION 运算符 2%l(qfN9
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。 SM}&
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B: EXCEPT 运算符 H2_6m5[&,
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。 j"0TAYmXwu
C: INTERSECT 运算符 c:DV8'fT
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。 <95*z @
注:使用运算词的几个查询结果行必须是一致的。 +C$wkx]
12、说明:使用外连接 V g7+G( ,
A、left outer join: AWZ4h,as{
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。 ~@^ pX*%i
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 OoOwEV2p_
B:right outer join: <SRSJJR|(
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。 Ze`ms96j{
C:full outer join: m,J9:S<5;
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。 FOa2VP%
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二、提升 .v) A|{:2
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) `yXHb
法一:select * into b from a where 1<>1 %H"AHkge:a
法二:select top 0 * into b from a _hB7;N3
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) <XpG5vV
insert into b(a, b, c) select d,e,f from b; AQ-R^kT
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) BBoVn^Z*R
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 !O,`Z`T?
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. )q+;+J`>
4、说明:子查询(表名1:a 表名2:b) Jl)Q#
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) \p iz Vt
5、说明:显示文章、提交人和最后回复时间 r2;+ACwWf_
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ;>p{|^X0D
6、说明:外连接查询(表名1:a 表名2:b) uoY]@.
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c U_0"1+jbq
7、说明:在线视图查询(表名1:a ) Yv;iduc('
select * from (SELECT a,b,c FROM a) T where t.a > 1; 6r5<uZ9w_X
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-?s8RD
select * from table1 where time between time1 and time2 -1F+,+m
select a,b,c, from table1 where a not between 数值1 and 数值2 9(9\kQj{C
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') Daf;;
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 ~<_PjV
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ~
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11、说明:四表联查问题: ~EhM"go
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 ..... r^"pLzAx
12、说明:日程安排提前五分钟提醒 L6pw'1'
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 "qY_O/Eg]]
13、说明:一条sql 语句搞定数据库分页 6[%4Q[
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 bq}o#d5p-_
14、说明:前10条记录 =
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select top 10 * form table1 where 范围 SQBe}FlktK
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.) 9r,7>#IF
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) oGZ%w4T
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 o7@81QA!e
(select a from tableA ) except (select a from tableB) except (select a from tableC) i\k>2df
17、说明:随机取出10条数据 )6-!,D0 db
select top 10 * from tablename order by newid() 7gbu7"Qc
18、说明:随机选择记录 Pu|3_3^
select newid() 7NfA)$
19、说明:删除重复记录 r7:4|6E
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) xcl8q:
20、说明:列出数据库里所有的表名 TqXB2`7Ri
select name from sysobjects where type='U' Z:%~Al:
21、说明:列出表里的所有的 "f`{4p0v
select name from syscolumns where id=object_id('TableName') n#5%{e>
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。 >BlF<
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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 n|I5ylt
显示结果: [[0u|`T/
type vender pcs ^5*9BwH`
电脑 A 1 ||kUi=5
电脑 A 1 )KD*G;<O]L
光盘 B 2 39,7N2 uY
光盘 A 2 |`6*~ciUV
手机 B 3 xrl!$xE
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手机 C 3 b\Gw|?Rv
23、说明:初始化表table1 ],ISWb
TRUNCATE TABLE table1 KdtQJ:_`k
24、说明:选择从10到15的记录 kEM|;&=_
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc uY|-: =
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三、技巧 n[`FoY
1、1=1,1=2的使用,在SQL语句组合时用的较多 <-m[0zgq
"where 1=1" 是表示选择全部 "where 1=2"全部不选, .qk_m-o
如: OuF%!~V
if @strWhere !='' 7^Q4?(A
begin c'~6 1HA<
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere YeCS`IXm
end s:\FlQ0
else x.~A vJ
begin }0~4Z)?e3
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 1|Z!8:&pj
end .:=G=v=1
我们可以直接写成 -mK;f$X
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere EG[Rda
2、收缩数据库 |.Y}2>{
--重建索引 &ywU^hBh
DBCC REINDEX =5m~rJ<{
DBCC INDEXDEFRAG DNl'}K1W
--收缩数据和日志 o&"nF+,
DBCC SHRINKDB aoVfvz2Y
DBCC SHRINKFILE ?#P@N4Uw}y
3、压缩数据库 R<n'v.~"A
dbcc shrinkdatabase(dbname) 1MnT*w
4、转移数据库给新用户以已存在用户权限 bs=x>F
exec sp_change_users_login 'update_one','newname','oldname' v46 5Z
go +GqUI~a
5、检查备份集 hMvLx>q3)
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ^9*kZV<K
6、修复数据库 Pwg?a
ALTER DATABASE [dvbbs] SET SINGLE_USER 0B?t:XU ,
GO TmIw?#q^
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK B)}.%G*
GO `suEN@^
ALTER DATABASE [dvbbs] SET MULTI_USER $,9A?'
GO &;]KntxB
7、日志清除 R-V4Ju[:
SET NOCOUNT ON I8:A]
DECLARE @LogicalFileName sysname, yvp$s
@MaxMinutes INT, RO+N>Wkt
@NewSize INT HJeZm
USE tablename -- 要操作的数据库名 eQqx0+-0c
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 TcM;6h`
@MaxMinutes = 10, -- Limit on time allowed to wrap log. qmx4hs8sh
@NewSize = 1 -- 你想设定的日志文件的大小(M) W2F *+M
-- Setup / initialize #XPY\n^k
DECLARE @OriginalSize int yO`HL'SMo
SELECT @OriginalSize = size B
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FROM sysfiles C=>IJ'G
WHERE name = @LogicalFileName Oq3]ZUVa
SELECT 'Original Size of ' + db_name() + ' LOG is ' + KJ;;825?
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + `}Z`aK
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' +<o}@hefY2
FROM sysfiles >q7/zl
WHERE name = @LogicalFileName mxfmK +'_
CREATE TABLE DummyTrans $\A=J
(DummyColumn char (8000) not null) LaCVI
DECLARE @Counter INT, waI:w,
@StartTime DATETIME, 'Wz`P#/
@TruncLog VARCHAR(255) +<1MY'>y
SELECT @StartTime = GETDATE(), zt|DHVy
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' g ONybz6]
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 6z keWR
EXEC (@TruncLog) kzuI<DW
-- Wrap the log if necessary. .ZK^kcyA
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired /\0g)B;]
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) A4>j4\A[M
AND (@OriginalSize * 8 /1024) > @NewSize (764-iv(
BEGIN -- Outer loop. 82*nC!P3E
SELECT @Counter = 0 'V#$PZx
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) zo>@"uH4
BEGIN -- update %ot4$eY
INSERT DummyTrans VALUES ('Fill Log') j| Hyv{sM
DELETE DummyTrans $4ZjN N@
SELECT @Counter = @Counter + 1 e"O c
END ]]^eIjg>a6
EXEC (@TruncLog) 6k-
END 'BOMFp7c
SELECT 'Final Size of ' + db_name() + ' LOG is ' + bc}BQ|Q
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 2Mo oqJp
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' {usv*Cm
FROM sysfiles \\UOpl
WHERE name = @LogicalFileName (@&+?A"6`
DROP TABLE DummyTrans &b:SDl6
SET NOCOUNT OFF &=S<StH
8、说明:更改某个表 s i=m5$V
exec sp_changeobjectowner 'tablename','dbo' ?)V?6"fFP
9、存储更改全部表 ;xxu ,
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch D(&XmC[\Y
@OldOwner as NVARCHAR(128), O=;}VZ<9
@NewOwner as NVARCHAR(128) _my!YS5n
AS !}pvrBS
DECLARE @Name as NVARCHAR(128) ews{0
DECLARE @Owner as NVARCHAR(128) A$o7<Hx
DECLARE @OwnerName as NVARCHAR(128) =jIP29+
DECLARE curObject CURSOR FOR eOU v#F
select 'Name' = name, (29BS(|!
'Owner' = user_name(uid) 6[~_;0
from sysobjects fIwG9cR
where user_name(uid)=@OldOwner fx3oA}
order by name 3 =-XA2zJ
OPEN curObject * ,#SwZ
FETCH NEXT FROM curObject INTO @Name, @Owner {&,MkWgG
WHILE(@@FETCH_STATUS=0) M>_
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BEGIN Lh
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if @Owner=@OldOwner :-)H
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begin 'M!* Ge
set @OwnerName = @OldOwner + '.' + rtrim(@Name) $WICyI{$
exec sp_changeobjectowner @OwnerName, @NewOwner ; &i