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。 #T[%6(QW
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一、基础 -7&?@M,u
1、说明:创建数据库 j+nv=p
CREATE DATABASE database-name (p^S~Ax
2、说明:删除数据库 FbmsN)mv!%
drop database dbname u9BjgK(M
3、说明:备份sql server k2pT1QZnt
--- 创建 备份数据的 device :fhB*SYK
USE master *aI~W^N3
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 3XnE y
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--- 开始 备份 # 9V'';:
BACKUP DATABASE pubs TO testBack RTZ:U@
4、说明:创建新表 Q~8y4=|#CY
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) hc"6u\>
根据已有的表创建新表: &eU3(F`.
A:create table tab_new like tab_old (使用旧表创建新表) f
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B:create table tab_new as select col1,col2... from tab_old definition only `6UtxJSx
5、说明:删除新表 W5|j1He&
drop table tabname )]3L/
6、说明:增加一个列 +eC3?B8rN
Alter table tabname add column col type uC)Zs, _5
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。 zqY)dk
7、说明:添加主键: Alter table tabname add primary key(col) ]uAS+shQ&
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....) gXF.on4B
删除索引:drop index idxname / xs9.w8-
注:索引是不可更改的,想更改必须删除重新建。 7pz\ScSe
9、说明:创建视图:create view viewname as select statement @\!ww/QT
删除视图:drop view viewname (xbIUz.
10、说明:几个简单的基本的sql语句 :4U0I:J#
选择:select * from table1 where 范围 2?*||c==*
插入:insert into table1(field1,field2) values(value1,value2) vsc&Ju%k
删除:delete from table1 where 范围 }{A?PHV5
更新:update table1 set field1=value1 where 范围 j"i#R1T
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! \x(.d.l/
排序:select * from table1 order by field1,field2 [desc] *CzCUu:%t
总数:select count as totalcount from table1 ;HP#bx
求和:select sum(field1) as sumvalue from table1 2p+C%"n>
平均:select avg(field1) as avgvalue from table1 ^B|YO8.v
最大:select max(field1) as maxvalue from table1 >r=6A
最小:select min(field1) as minvalue from table1
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11、说明:几个高级查询运算词 brfKd]i
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A: UNION 运算符 "U*5Z:8?9
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。 YroNpu]s
B: EXCEPT 运算符 .x>HA^4
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。 %OEq,Tb
C: INTERSECT 运算符 FZH-q!"^cK
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。 Ajg\aof0{
注:使用运算词的几个查询结果行必须是一致的。 uS&LG#a
12、说明:使用外连接 JA< :K0
A、left outer join: jAZ >mo[
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。 1g~y]iQ
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 A*R n<{U
B:right outer join: o _(0
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。 7pP+5&*
C:full outer join: <&6u]uKrW
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。 D,E$_0
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二、提升 &>g~-s
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) N2[jO+6
法一:select * into b from a where 1<>1 F;-90w
法二:select top 0 * into b from a l=xt;c!
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ^EuW(
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insert into b(a, b, c) select d,e,f from b; d+Ds9(gV
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) R3Ee%0QK
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 /'\;8A$J`
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. c_Tzyh7l4
4、说明:子查询(表名1:a 表名2:b) MUB37
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) M!#AfIyB
5、说明:显示文章、提交人和最后回复时间 E23w *']
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b NHAH#7]M&1
6、说明:外连接查询(表名1:a 表名2:b) bNXAU\M^
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c @C=M
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7、说明:在线视图查询(表名1:a ) #52NsVaT@
select * from (SELECT a,b,c FROM a) T where t.a > 1; |by@ :@*y
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 /p 5=i
select * from table1 where time between time1 and time2 vf N#NY6
select a,b,c, from table1 where a not between 数值1 and 数值2 &wb9_?ir-
9、说明:in 的使用方法 p/3BD&6
select * from table1 where a [not] in ('值1','值2','值4','值6') [Y$V\h=V
10、说明:两张关联表,删除主表中已经在副表中没有的信息 d/lffNS=
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) R:f7LRF/\
11、说明:四表联查问题: -%H%m`wD
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... [IMQIX
12、说明:日程安排提前五分钟提醒 'bPk'pj9
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 wFb@1ae\
13、说明:一条sql 语句搞定数据库分页 2f^-~dz
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 Y&g&n o_
14、说明:前10条记录 1}nm2h1 I
select top 10 * form table1 where 范围 Oy%Im8.-A#
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) :!']p2B
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ~~q}cywBk
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 x9~[HuJ
(select a from tableA ) except (select a from tableB) except (select a from tableC) 4w;~4#ZPp
17、说明:随机取出10条数据 lLMPw}r<
select top 10 * from tablename order by newid() hlC%HA
18、说明:随机选择记录 ]-a{IWVN
select newid() R6<4"?*r
19、说明:删除重复记录 Cg3ODfe
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) H-2_j
20、说明:列出数据库里所有的表名 9n 6fXOC
select name from sysobjects where type='U' 3q?5OL^$
21、说明:列出表里的所有的 )88nMH-
select name from syscolumns where id=object_id('TableName') vhpvO>Q
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。 0bSz4<}
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 : u-.T.zZl
显示结果: )
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type vender pcs N Bz%(?\
电脑 A 1 ^K;hn,R=
电脑 A 1 Pin/qp&Fa8
光盘 B 2 "{ FoA3g|
光盘 A 2 yd*3)6=
手机 B 3 { *$9,
手机 C 3 auL^%M|$R
23、说明:初始化表table1 |Euus5[
TRUNCATE TABLE table1 Pr/]0<s
24、说明:选择从10到15的记录 'evv,Q{87
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 4TVwa(cB
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三、技巧 L=g_@b
1、1=1,1=2的使用,在SQL语句组合时用的较多 +v-LL*fa
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ?ZX!7^7
如: ;{Jb6'K1h
if @strWhere !='' 4|f}F
begin " '[hr$h3
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Ag6uR(uI
end l[*sHi
else o_rtH|ntX5
begin Q7(eq0na
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' aS/`A
end ve-8*Xa
我们可以直接写成 Xm@aYNV
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ]! )xr
2、收缩数据库 s#P:6]Ar
--重建索引 JO}?.4B
DBCC REINDEX <+q$XL0
DBCC INDEXDEFRAG }"4roJ
--收缩数据和日志 L$hc,
DBCC SHRINKDB 3]`mQm E
DBCC SHRINKFILE 8K^f:)Qw
3、压缩数据库 2kJ!E@n7
dbcc shrinkdatabase(dbname)
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4、转移数据库给新用户以已存在用户权限 !
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exec sp_change_users_login 'update_one','newname','oldname' choL%g}
go S_5?U2%D
5、检查备份集 r0Z+RB^I
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' h.^o)T
6、修复数据库 xYwkFB$$*
ALTER DATABASE [dvbbs] SET SINGLE_USER a(|xw
GO 4E'|.tt(
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 85hQk+Bu4
GO U`1l8'W}:#
ALTER DATABASE [dvbbs] SET MULTI_USER 0'@u!m?
GO ohsH 2]C
7、日志清除 =G>.-Qfs
SET NOCOUNT ON PG"@A
DECLARE @LogicalFileName sysname, 1i+FL''
@MaxMinutes INT, [Xh\mDU.
@NewSize INT (#z;(EN0t
USE tablename -- 要操作的数据库名 = t-fYV
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 x.\XUJ4x
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 50,Y
@NewSize = 1 -- 你想设定的日志文件的大小(M) 9[sG1eP!
-- Setup / initialize {82rne`[
DECLARE @OriginalSize int 045\i[l=
SELECT @OriginalSize = size ^ $wJi9D6
FROM sysfiles o&,Y<$!:VH
WHERE name = @LogicalFileName -#%X3F7/w
SELECT 'Original Size of ' + db_name() + ' LOG is ' + N8 M'0i?
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ^jOCenE3
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' QT;Va#a
FROM sysfiles |z+9km7,
WHERE name = @LogicalFileName @>:i-5
CREATE TABLE DummyTrans VF=Z`
(DummyColumn char (8000) not null) T<M?PlED
DECLARE @Counter INT, <A{y($
@StartTime DATETIME, N]u2ql&
@TruncLog VARCHAR(255) J 8q
SELECT @StartTime = GETDATE(), ] R<FKJ[
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 4,zvFH*AH
DBCC SHRINKFILE (@LogicalFileName, @NewSize) J|q^+K
EXEC (@TruncLog) uP Rl[tS0
-- Wrap the log if necessary. gY%&IHQ'
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired |!xpYT:
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Rn;VP:H M
AND (@OriginalSize * 8 /1024) > @NewSize @p6@a6N%
BEGIN -- Outer loop. */Cj$KY70
SELECT @Counter = 0 6qDfcs
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) h"8QeX:((
BEGIN -- update e{JVXc[D
INSERT DummyTrans VALUES ('Fill Log') 6WO7+M;z
DELETE DummyTrans :])JaS^
SELECT @Counter = @Counter + 1 > [8#hSk
END S\b K+
EXEC (@TruncLog) niQcvnT4b
END *;P2+cE>H3
SELECT 'Final Size of ' + db_name() + ' LOG is ' + /.2 qWQH
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 9fMSAB+c%
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' .?Auh2nr
FROM sysfiles Q]T BQ&
WHERE name = @LogicalFileName /sV?JV[t
DROP TABLE DummyTrans @`Wt4<
SET NOCOUNT OFF 6W:1>,xS
8、说明:更改某个表 #!L%J<MX
exec sp_changeobjectowner 'tablename','dbo' fa yKM
9、存储更改全部表 [G=:?J,P
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 5y}BCY2=/
@OldOwner as NVARCHAR(128), KqK9X
@NewOwner as NVARCHAR(128) W\NG>t
AS hbH#Co~o4#
DECLARE @Name as NVARCHAR(128) ke^d8Z.
DECLARE @Owner as NVARCHAR(128) *:[b'D!A
DECLARE @OwnerName as NVARCHAR(128)
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DECLARE curObject CURSOR FOR 5pmQp}}R
select 'Name' = name, o~k;D{Snr
'Owner' = user_name(uid) vS#{-X
from sysobjects @ge
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where user_name(uid)=@OldOwner C
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order by name zu C5@jy.x
OPEN curObject 2md.S$V$,
FETCH NEXT FROM curObject INTO @Name, @Owner PK}vh%
WHILE(@@FETCH_STATUS=0) ?^F5(B[+Y
BEGIN EU9[F b]
if @Owner=@OldOwner )6 k1 P
begin 3u4:l
set @OwnerName = @OldOwner + '.' + rtrim(@Name) VAg68EbnF
exec sp_changeobjectowner @OwnerName, @NewOwner dxntGH< O
end `$M
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-- select @name,@NewOwner,@OldOwner mV%h[~-
FETCH NEXT FROM curObject INTO @Name, @Owner ]Ly8s#<g]N
END D Kq-C%
close curObject ? osfL
deallocate curObject %b9fW
GO ]xYa yN!n
10、SQL SERVER中直接循环写入数据 &8afl"_~
declare @i int s_v}=C^
set @i=1 @'Q%Jc(
while @i<30 e lay
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begin 9ClF<5?M
insert into test (userid) values(@i) 4M7^
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set @i=@i+1 3@'lIV
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end ^1Yo-T(R
小记存储过程中经常用到的本周,本月,本年函数 uD[^K1Ag]^
Dateadd(wk,datediff(wk,0,getdate()),-1) 0H<4+
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Dateadd(wk,datediff(wk,0,getdate()),6) Z7oaQ\fR
Dateadd(mm,datediff(mm,0,getdate()),0) @f%wd2
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) )lOji7&e
Dateadd(yy,datediff(yy,0,getdate()),0) {<r`5
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) G_0)oC@Jl:
上面的SQL代码只是一个时间段 `;e^2
Dateadd(wk,datediff(wk,0,getdate()),-1) gLV^Z6eE
Dateadd(wk,datediff(wk,0,getdate()),6) "&}mAWT%If
就是表示本周时间段. )6g&v'dq
下面的SQL的条件部分,就是查询时间段在本周范围内的: "d2LyQy
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) l)H9J]
而在存储过程中 g/6nwa
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) (<n>EF#
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 1P \up