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。 Zh,]J `
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一、基础 J @B4
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1、说明:创建数据库 k4R4YI"jV
CREATE DATABASE database-name -S$$/sR
2、说明:删除数据库 ,}<RrUfD
drop database dbname 76cEKHa<
3、说明:备份sql server -+P7:4/
--- 创建 备份数据的 device /f&By
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USE master b *9-}g:
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' `a'`$'j
--- 开始 备份 k1iLnza%
BACKUP DATABASE pubs TO testBack ('d{t:TsY
4、说明:创建新表 b42QBTeg
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ~4 ^p}{
根据已有的表创建新表: @1.9PR$x
A:create table tab_new like tab_old (使用旧表创建新表) ]fC7%"nB
B:create table tab_new as select col1,col2... from tab_old definition only IMaYEO[
5、说明:删除新表 $8@+j[>
drop table tabname W 5I=X]&
6、说明:增加一个列 STB-guia5
Alter table tabname add column col type mJ$Htyr
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。 Tc_do"uU
7、说明:添加主键: Alter table tabname add primary key(col) 6ZksqdP8
说明:删除主键: Alter table tabname drop primary key(col) :#SNpn=@
8、说明:创建索引:create [unique] index idxname on tabname(col....) \HG$V>2
删除索引:drop index idxname s##Ay{
注:索引是不可更改的,想更改必须删除重新建。 ^
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9、说明:创建视图:create view viewname as select statement .K7C-Xn=
删除视图:drop view viewname 6Ahr_{
10、说明:几个简单的基本的sql语句 /e<5Np\X
选择:select * from table1 where 范围 6
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插入:insert into table1(field1,field2) values(value1,value2) Ilef+V^qr
删除:delete from table1 where 范围 GZ"/k<~0
更新:update table1 set field1=value1 where 范围 CWvlr nv
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! n?Z f/T
排序:select * from table1 order by field1,field2 [desc] %~\
总数:select count as totalcount from table1 gvo?([j-m
求和:select sum(field1) as sumvalue from table1 v= 8VvT8
平均:select avg(field1) as avgvalue from table1 Ky6+~>
最大:select max(field1) as maxvalue from table1 6eo4#/+%
最小:select min(field1) as minvalue from table1 I61%H9;
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11、说明:几个高级查询运算词 Y Z\@)D;
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A: UNION 运算符 )JX$/-
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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。 hr1$1&p
B: EXCEPT 运算符 R8uj3!3^
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。 `WlH*p)z9
C: INTERSECT 运算符 *|poxT G
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。 j"6:A
注:使用运算词的几个查询结果行必须是一致的。 >KHp-|0pv
12、说明:使用外连接
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A、left outer join: qp@m&GH
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。 DO%Pwfkd
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 , QA9k$`
B:right outer join: ifHU|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。 4y>(RrVG
C:full outer join: !l"tI#?6W%
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。 a7=YG6[
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二、提升 re q-Q |
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) XLocg
法一:select * into b from a where 1<>1 \-d'9b ?
法二:select top 0 * into b from a 7@@<5&mN
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) m2ox8(sd
insert into b(a, b, c) select d,e,f from b;
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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) j%u8=
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 $^IjFdD
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ,P~QS
4、说明:子查询(表名1:a 表名2:b) 94YA2_f;
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) 3 69Zu4|u
5、说明:显示文章、提交人和最后回复时间 FH[#yq.Pr
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b b?>VPuyBb
6、说明:外连接查询(表名1:a 表名2:b) )r pD2H
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c {s9<ej~<R
7、说明:在线视图查询(表名1:a ) I3An57YV].
select * from (SELECT a,b,c FROM a) T where t.a > 1; M#T#:wf~
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 qzHU)Ns(_
select * from table1 where time between time1 and time2 ~.H~XKw
select a,b,c, from table1 where a not between 数值1 and 数值2 *F..ZS'$[
9、说明:in 的使用方法 7P
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select * from table1 where a [not] in ('值1','值2','值4','值6') {yU0D*#6
10、说明:两张关联表,删除主表中已经在副表中没有的信息 w-M7opkq
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) vuW-}fY;
11、说明:四表联查问题: -`g J
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 ..... SlT7L||Ww
12、说明:日程安排提前五分钟提醒 ;tXY =
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ;xI0\a7
13、说明:一条sql 语句搞定数据库分页 _^-D _y
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 df yrn%^Ia
14、说明:前10条记录 #XfT1
select top 10 * form table1 where 范围 3jS7 uU
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.) &rcdr+'
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) s4N,^_j
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 xlk5Gob*
(select a from tableA ) except (select a from tableB) except (select a from tableC) {F/q{c~]
17、说明:随机取出10条数据 E;$$+rA
select top 10 * from tablename order by newid() <ipWMZae0F
18、说明:随机选择记录 9LHa&""
select newid() r;$r=Uf r
19、说明:删除重复记录 \D ^7Z97
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) eq{
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20、说明:列出数据库里所有的表名 0yKhp:^
select name from sysobjects where type='U' C,(j$Id
21、说明:列出表里的所有的 t)KPp|&
select name from syscolumns where id=object_id('TableName') ~Z7)x7
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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。 1S&0
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 A^t"MYX@
显示结果: R7,pukK
type vender pcs B9AbKK$`
电脑 A 1 /RMer
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电脑 A 1 PQ i
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光盘 B 2 5e)i!;7Uv
光盘 A 2 >r~|1kQ.
手机 B 3 /K[]B]1NE
手机 C 3 ^SgN(-QH
23、说明:初始化表table1 $.;iu2iyo
TRUNCATE TABLE table1 aI7Xq3
24、说明:选择从10到15的记录 fH; |Rm
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc t={po QC~
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三、技巧 !#C)99L"F
1、1=1,1=2的使用,在SQL语句组合时用的较多 w gmWo8
"where 1=1" 是表示选择全部 "where 1=2"全部不选, yX`J7O{=
如: UYH|?Jw!N
if @strWhere !='' /8:gVXZi
begin }tu4z+T2
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere t Z+0}d
end mqubXS;J|P
else + 2OZJVJ
begin {({
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' =1eV
end G}Gb|sD
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我们可以直接写成 UC.8DaIPN
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere DhHtz.6
2、收缩数据库 z"9aAytd
--重建索引 r.?qEe8VV
DBCC REINDEX Un]DFu
DBCC INDEXDEFRAG 6<#Slw[
--收缩数据和日志 V, E9Uds
DBCC SHRINKDB *Gf&q
DBCC SHRINKFILE =Z^un&'
3、压缩数据库 ykJ+%gla
dbcc shrinkdatabase(dbname) zI(xSX@
4、转移数据库给新用户以已存在用户权限 g^qz&;R]
exec sp_change_users_login 'update_one','newname','oldname' .iN-4"_j1
go )7tV*=?Ic8
5、检查备份集 e<kpcF5{\
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' XadG\_?t`
6、修复数据库 L(W%~UGN
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ALTER DATABASE [dvbbs] SET SINGLE_USER LE<:.?<Z-
GO PKl]GegP
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK MK<
GO 6^WiZ^~
ALTER DATABASE [dvbbs] SET MULTI_USER <##|311o
GO fi5YMYd1
7、日志清除 C+DG+_%V*S
SET NOCOUNT ON _xa}B,H
DECLARE @LogicalFileName sysname, ex{)mE4Cd
@MaxMinutes INT, ',:3>{9
@NewSize INT XC
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USE tablename -- 要操作的数据库名 d~w}NK[(
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 hkkF1
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. NJ.rv
@NewSize = 1 -- 你想设定的日志文件的大小(M) ,"x23=]
-- Setup / initialize N `J:^,H
DECLARE @OriginalSize int L00Sp#$\
SELECT @OriginalSize = size 2*N&q|ED
FROM sysfiles ys:1Z\$P
WHERE name = @LogicalFileName <WO&$&
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ?a*fy}A|
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + zw}@nqp
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' .i1jFwOd|G
FROM sysfiles b0!*mrF]6
WHERE name = @LogicalFileName lO%MyP
CREATE TABLE DummyTrans M-{b
(DummyColumn char (8000) not null) vd2uD2%con
DECLARE @Counter INT, Q@PJ)fwN
@StartTime DATETIME, &8pCHGmV)
@TruncLog VARCHAR(255) (7M^-_q]D
SELECT @StartTime = GETDATE(), 0*/mc9 6
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' (xI)"{
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Tnzco
EXEC (@TruncLog) VaOpO8y`
-- Wrap the log if necessary. AN|jFSQ'
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Xw&QrTDS`
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) zv8aV2?D
AND (@OriginalSize * 8 /1024) > @NewSize r)) $XM
BEGIN -- Outer loop. em f0sL
SELECT @Counter = 0 ;D%$Eh&oma
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) AsTMY02|
BEGIN -- update Fr1;)WV
INSERT DummyTrans VALUES ('Fill Log') md1EJ1\14
DELETE DummyTrans nF|#@O`1
SELECT @Counter = @Counter + 1 #j(q/
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END \]tq7
EXEC (@TruncLog) <1;,B%_^
END MzBfHt'Rk
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 23(B43zy
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ,-w-su=J_
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' $)kk8Q4+K
FROM sysfiles hY\Eh.
WHERE name = @LogicalFileName Q
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DROP TABLE DummyTrans 7j9D;_(.^$
SET NOCOUNT OFF o=mq$Z:}
8、说明:更改某个表 0X] ekq
exec sp_changeobjectowner 'tablename','dbo' 4d{"S02h
9、存储更改全部表 r[C3u[
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch GC5#1+fQ
@OldOwner as NVARCHAR(128), U89]?^|bb
@NewOwner as NVARCHAR(128) L%c]%3A
AS 8:3oH!n
DECLARE @Name as NVARCHAR(128) 9,Crmbw8
DECLARE @Owner as NVARCHAR(128) @lb=-oR!~
DECLARE @OwnerName as NVARCHAR(128) "1gk-
DECLARE curObject CURSOR FOR 2?#y
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select 'Name' = name, M"$jpBN*
'Owner' = user_name(uid)
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from sysobjects 3{N p 9y.
where user_name(uid)=@OldOwner <> &e/
order by name J4Q)`Y\~
OPEN curObject .ruz l(6
FETCH NEXT FROM curObject INTO @Name, @Owner rw}5nv
WHILE(@@FETCH_STATUS=0) a}[=_vb}K
BEGIN :IP;FrcMP
if @Owner=@OldOwner $S($97IU=
begin g:~?U*f-
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ZNL;8sI?>
exec sp_changeobjectowner @OwnerName, @NewOwner *@$($<pY&
end Z9;nC zHm
-- select @name,@NewOwner,@OldOwner qd#(`%_/
FETCH NEXT FROM curObject INTO @Name, @Owner ]yj4~_&O
END
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close curObject (Fbm9(q$d
deallocate curObject ne!j%9Ar
GO 7gZVg@
10、SQL SERVER中直接循环写入数据 q/ d5P
declare @i int 1pYmtr
set @i=1 0`g}(}'L
while @i<30 `JY>v io
begin |p=.Gg=2
insert into test (userid) values(@i) b]tA2~e
set @i=@i+1 n]6}yJJo
end @4 Os?_gJ\
小记存储过程中经常用到的本周,本月,本年函数 E7Gi6w~\
Dateadd(wk,datediff(wk,0,getdate()),-1) %>I?'y^
Dateadd(wk,datediff(wk,0,getdate()),6) M2zos(8g
Dateadd(mm,datediff(mm,0,getdate()),0) "c !oOaA
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) kMJQeo79
Dateadd(yy,datediff(yy,0,getdate()),0) WacU@L $A
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) KL:6P-3
上面的SQL代码只是一个时间段 c4qp3B_w
Dateadd(wk,datediff(wk,0,getdate()),-1) ^J#*n;OQ3A
Dateadd(wk,datediff(wk,0,getdate()),6) Ht=6P)
就是表示本周时间段. ?hry=I(7r
下面的SQL的条件部分,就是查询时间段在本周范围内的: k^'d@1z;C
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) tLoD"/z
而在存储过程中 :#Ex3H7
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Im' :sJ31
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Z CQt1;