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。 ztp|FUi
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一、基础 gOF^?M11x
1、说明:创建数据库 +nYFLe
CREATE DATABASE database-name t G_4>-Y#w
2、说明:删除数据库 U1\7Hcs$
drop database dbname 5`h$^l/
3、说明:备份sql server $n<a`PdH
--- 创建 备份数据的 device qC`}vr|Z
USE master s.J4&2Q
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' rc_m{.b
--- 开始 备份 3H2~?CaJ
BACKUP DATABASE pubs TO testBack ;V,L_"/X
4、说明:创建新表 M2Q,&>M
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) +x]/W|5
根据已有的表创建新表: sz9W}&(j
A:create table tab_new like tab_old (使用旧表创建新表) ! M^O\C)
B:create table tab_new as select col1,col2... from tab_old definition only nI:M!j5s`
5、说明:删除新表 bRAD_
drop table tabname q
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6、说明:增加一个列 U5Hi9fe
Alter table tabname add column col type OBi(]l}^O
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。 z; GQnAG@
7、说明:添加主键: Alter table tabname add primary key(col) __=53]jGE
说明:删除主键: Alter table tabname drop primary key(col) !se1W5ke#
8、说明:创建索引:create [unique] index idxname on tabname(col....) ;cMQ0e
删除索引:drop index idxname V}y]<
注:索引是不可更改的,想更改必须删除重新建。 (`(D
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9、说明:创建视图:create view viewname as select statement g p:0 Y
删除视图:drop view viewname u*C*O4f>OC
10、说明:几个简单的基本的sql语句 9nFL70
选择:select * from table1 where 范围 _3Eo{^
插入:insert into table1(field1,field2) values(value1,value2) $qD\ku;'
删除:delete from table1 where 范围 ~F"S]
更新:update table1 set field1=value1 where 范围 ]?6wU-a
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! /.]u%;%r[
排序:select * from table1 order by field1,field2 [desc] &5W;E+Pub
总数:select count as totalcount from table1 3x~7N
求和:select sum(field1) as sumvalue from table1 x,gk]C f
平均:select avg(field1) as avgvalue from table1 ?%,LZw^[
最大:select max(field1) as maxvalue from table1 QAkK5,`vV.
最小:select min(field1) as minvalue from table1 Fb{N>*l.
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11、说明:几个高级查询运算词 vl:~&I&y;R
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A: UNION 运算符 xJ>5 ol
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。 coXg]bUKo
B: EXCEPT 运算符 \c2x
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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。 \,13mB6
C: INTERSECT 运算符 ,C,nNaW
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。 h$8h@2%
注:使用运算词的几个查询结果行必须是一致的。 JCcYFtW
12、说明:使用外连接 _d 6'f8[&
A、left outer join: d*8*9CpO:
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 Z@s[8wrmPl
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Va )W[I
B:right outer join: f2e;N[D
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 t=B1yvE"
C:full outer join: qur2t8gnxq
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 C>|.0:[%
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二、提升 Gwk$<6E
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用)
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法一:select * into b from a where 1<>1 3CD#OCz7&
法二:select top 0 * into b from a Erw1y,mF
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) &|x7T<,)
insert into b(a, b, c) select d,e,f from b; 9)wYSz'
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) ~61b^L}$
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 >@7$=Y>D
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. >B6*`3v
4、说明:子查询(表名1:a 表名2:b) ]EKg)E
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) <|l}@\iRX
5、说明:显示文章、提交人和最后回复时间 M{ncWq*_j
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b u)<]Pb})r
6、说明:外连接查询(表名1:a 表名2:b) eA7
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c @eJ8wf]
7、说明:在线视图查询(表名1:a ) u"&?u+1j
select * from (SELECT a,b,c FROM a) T where t.a > 1; PIU@}:}
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 Ah1
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select * from table1 where time between time1 and time2 nYSe0w
select a,b,c, from table1 where a not between 数值1 and 数值2 *k7BE_&*0Z
9、说明:in 的使用方法 Qa,=
select * from table1 where a [not] in ('值1','值2','值4','值6') E!ndXz 59
10、说明:两张关联表,删除主表中已经在副表中没有的信息 9)7$U QY
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) YVccO~!8
11、说明:四表联查问题: c*r H^Nz
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 ..... US$$ADq
12、说明:日程安排提前五分钟提醒 bB?E(>N;
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 1dLc/,|
13、说明:一条sql 语句搞定数据库分页 (6$P/k8
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 j Mn,N9Mf
14、说明:前10条记录 e' M&Eh
select top 10 * form table1 where 范围 N" L&Z4Z
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.) 4`i8m
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) "jAd.x?X7e
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 $A?9U}V#^
(select a from tableA ) except (select a from tableB) except (select a from tableC) }sH[_%)
17、说明:随机取出10条数据 +4-T_m/W/
select top 10 * from tablename order by newid() 4fsd5#
18、说明:随机选择记录 SO6)FiPy!n
select newid() G0 EXgq8
19、说明:删除重复记录 BsFO]F5mmX
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) I#MPJ@*WT
20、说明:列出数据库里所有的表名 z[f]mU
select name from sysobjects where type='U' QDn_`c
21、说明:列出表里的所有的 6!]@S|vDX
select name from syscolumns where id=object_id('TableName') &`qYe)1Eo
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 QG*hQh
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type lf`ULY4{
显示结果: vt5w(}v(
type vender pcs K F'fg
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电脑 A 1 {O>Td9
电脑 A 1 'b.jKkW7
光盘 B 2
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光盘 A 2 d`=
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手机 B 3 =u2~=t=LV
手机 C 3 Wq3PN^
23、说明:初始化表table1 )"\=
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TRUNCATE TABLE table1 -dovk?'Gj
24、说明:选择从10到15的记录 cI[i v
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc fcdXj_u
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三、技巧 P1OYS\
1、1=1,1=2的使用,在SQL语句组合时用的较多 :WWHEZK
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Ei:m@}g
如: L&+k`b
if @strWhere !='' eM!Oc$C8[
begin 0dwD ?GG2
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 9 5!xJdq
end ,$!fyi[;C
else gA=Pz[i)p
begin r4u,I<ZbH
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' b6S"&hs
end iJh{,0))g
我们可以直接写成 <!t;[ie?y
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 8cfsl lI
2、收缩数据库 I 8i|tQz
--重建索引 )PR`irw
DBCC REINDEX %ly&~&0
DBCC INDEXDEFRAG rui 8x4c
--收缩数据和日志 T=w0T-[f
DBCC SHRINKDB I.t)sf,
DBCC SHRINKFILE >Ch2Ep
3、压缩数据库 lrPIXIM
dbcc shrinkdatabase(dbname) E
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4、转移数据库给新用户以已存在用户权限 i*l=xW;bM
exec sp_change_users_login 'update_one','newname','oldname' [2Y@O7;nI
go >G1]#'6;
5、检查备份集 ;]R5:LbXS
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ymrnu-p o
6、修复数据库 cC9Zc#aK
ALTER DATABASE [dvbbs] SET SINGLE_USER "WY5Pzsi:
GO w[vccARQ
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK .,VLQbtg
GO `+."X1
ALTER DATABASE [dvbbs] SET MULTI_USER "8)%XSb
GO K
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7、日志清除 &n?RKcH}d
SET NOCOUNT ON 1e9~):C~W
DECLARE @LogicalFileName sysname, ?;w`hA3ei
@MaxMinutes INT, #3>jgluM'
@NewSize INT +i /4G.=*
USE tablename -- 要操作的数据库名 `o{_+Li9
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 C!K&d,M
@MaxMinutes = 10, -- Limit on time allowed to wrap log. )~xH!%4F
@NewSize = 1 -- 你想设定的日志文件的大小(M) _`*G71PS
-- Setup / initialize > B;YYj~f}
DECLARE @OriginalSize int ,9KnC=_y
SELECT @OriginalSize = size !mVq+_7]
FROM sysfiles I(3YXv
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WHERE name = @LogicalFileName ~md06"AYJ
SELECT 'Original Size of ' + db_name() + ' LOG is ' + <v\$r2C*
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + r~|7paX!
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' H7drDw
FROM sysfiles Q`O~ f<a
WHERE name = @LogicalFileName );S8`V
CREATE TABLE DummyTrans ^IvQdVB
(DummyColumn char (8000) not null) }YiFiGf,
DECLARE @Counter INT, y(a>Y! dgU
@StartTime DATETIME, $E8}||d
@TruncLog VARCHAR(255) k:mW ,s|a
SELECT @StartTime = GETDATE(), =pj3G?F#
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ?{L'd
DBCC SHRINKFILE (@LogicalFileName, @NewSize) A*|\E:fo
EXEC (@TruncLog) EKuLt*a/
-- Wrap the log if necessary. =|fB":vk
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired SpIiMu(
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) _$vbb#QXZG
AND (@OriginalSize * 8 /1024) > @NewSize s`yg?CR`,
BEGIN -- Outer loop. oZL# *Z(h
SELECT @Counter = 0 2J)
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 8wkt9:
BEGIN -- update 3_&s'sG5
INSERT DummyTrans VALUES ('Fill Log') &-My[t
DELETE DummyTrans 4,=;:#n,J
SELECT @Counter = @Counter + 1 ! P$[$W
END s I 0:<6W
EXEC (@TruncLog) M`*
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END z63y8
SELECT 'Final Size of ' + db_name() + ' LOG is ' + s=K?-O
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + M D&7k,!
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' L@?3E`4/v
FROM sysfiles p%#'`*<a_
WHERE name = @LogicalFileName #oR@!?
DROP TABLE DummyTrans YPKB4p#
SET NOCOUNT OFF >oi?aD%
8、说明:更改某个表 \IqCC h
exec sp_changeobjectowner 'tablename','dbo' >$a;+v
9、存储更改全部表 :N_DJ51
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch (bB"6
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@OldOwner as NVARCHAR(128), iG=Di)O
@NewOwner as NVARCHAR(128) 6y^GMlsI
AS {#pwr WG
DECLARE @Name as NVARCHAR(128) Wn?),=WQ{
DECLARE @Owner as NVARCHAR(128) \#N?
DECLARE @OwnerName as NVARCHAR(128) f)r6F JLU
DECLARE curObject CURSOR FOR ##alzC
select 'Name' = name, xm=$D6O:
'Owner' = user_name(uid) `z7,HJ.0c
from sysobjects O{U j
where user_name(uid)=@OldOwner @a
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order by name h7o.RRhK
OPEN curObject $ 1m}lXk
FETCH NEXT FROM curObject INTO @Name, @Owner vWa\8y f
WHILE(@@FETCH_STATUS=0) :V_UJ3xf
BEGIN m4'jTC$
if @Owner=@OldOwner kZi/2UA5Z
begin mGkQx
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) ?|\wJrM ]
exec sp_changeobjectowner @OwnerName, @NewOwner 0y+i?y
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end ?a1pO#{Dg
-- select @name,@NewOwner,@OldOwner +m/n~-6q
FETCH NEXT FROM curObject INTO @Name, @Owner \F""G,AWq{
END 8yH)9#>
close curObject f"zmN G'
deallocate curObject P|C5k5
GO ~CdW:t
10、SQL SERVER中直接循环写入数据 Wu8^Z Z{
declare @i int $q.}eb0
set @i=1 ooC9a>X
while @i<30 JZ&_1~Z=
begin t%<y^Wa=
insert into test (userid) values(@i) Q(e
set @i=@i+1 h ^s8LE3
end k1s5cg=n(
小记存储过程中经常用到的本周,本月,本年函数 @7V~CNB+
Dateadd(wk,datediff(wk,0,getdate()),-1) n+i=Ff
Dateadd(wk,datediff(wk,0,getdate()),6) \<G"9w
Dateadd(mm,datediff(mm,0,getdate()),0) ED>a'y$f
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Fmz+ Xb
Dateadd(yy,datediff(yy,0,getdate()),0) ;-;lM6zP
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) P|]r*1^5
上面的SQL代码只是一个时间段 "^a"`?J
Dateadd(wk,datediff(wk,0,getdate()),-1) z0 #2?o
Dateadd(wk,datediff(wk,0,getdate()),6) \k{[HfVvn
就是表示本周时间段. p(8 @
下面的SQL的条件部分,就是查询时间段在本周范围内的: jIVD i~Ld
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) %H2ios[UO
而在存储过程中 ,VSO;:Z
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ;[(d=6{hc]
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) N-Z=p)]