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。 (8*& 42W
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一、基础 T;u>]"S
1、说明:创建数据库 !pNY`sw}
CREATE DATABASE database-name ZxRD+`
2、说明:删除数据库 kN)m"}gX
drop database dbname ~+GMn[h
3、说明:备份sql server LOkNDmj
--- 创建 备份数据的 device 6k=ink-/
USE master T"2D<7frbo
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ;&Oma`Ec
--- 开始 备份 9rn[46s`
BACKUP DATABASE pubs TO testBack >|[74#}7
4、说明:创建新表 MOIH%lpe
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) `<C/-Au
根据已有的表创建新表: B0^0d*8t|@
A:create table tab_new like tab_old (使用旧表创建新表) B0KZdBRx}
B:create table tab_new as select col1,col2... from tab_old definition only mt+IB4`
5、说明:删除新表 0O,l
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drop table tabname 4ZK8Y[]Lv
6、说明:增加一个列 wM;9plYlw0
Alter table tabname add column col type ,ij"&XA
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。 45hjN6
7、说明:添加主键: Alter table tabname add primary key(col) bw8~p%l?
说明:删除主键: Alter table tabname drop primary key(col) (Hcd{]M~
8、说明:创建索引:create [unique] index idxname on tabname(col....) &a>fZ^Y=k
删除索引:drop index idxname T{iv4`'
注:索引是不可更改的,想更改必须删除重新建。 EEaf/D/ jt
9、说明:创建视图:create view viewname as select statement 2B#
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删除视图:drop view viewname ,4-) e
10、说明:几个简单的基本的sql语句 )k.[Ve
选择:select * from table1 where 范围 'wd-!aZAd
插入:insert into table1(field1,field2) values(value1,value2) SY`
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删除:delete from table1 where 范围 A(mU,^
更新:update table1 set field1=value1 where 范围 "(hhb>V1Wl
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! R^.oM1qu|
排序:select * from table1 order by field1,field2 [desc] =-`}(b2N
总数:select count as totalcount from table1 *:q3<\y{
求和:select sum(field1) as sumvalue from table1 pN)9GO5
平均:select avg(field1) as avgvalue from table1 @eRR#S
最大:select max(field1) as maxvalue from table1 l!plw,PYC
最小:select min(field1) as minvalue from table1 &sp7YkaW
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11、说明:几个高级查询运算词 Ocq.<#||H
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A: UNION 运算符 n#
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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。 u6AReL'f
B: EXCEPT 运算符 IRemF@
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。 <|NP!eMsw8
C: INTERSECT 运算符 4eym$UWw
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。 ;[]{O5TB
注:使用运算词的几个查询结果行必须是一致的。 :!M/9D*}0
12、说明:使用外连接 #ra~Yb-F
A、left outer join: V fJYYR
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。 vs/.'yD/C
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 vr|9NP]v
B:right outer join: !_VKJZuH
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。 Lt+ Cm$3
C:full outer join: ngprTMO$&
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。 ,%#FK|
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二、提升 ~n$VCLa
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) fPf8hz>
法一:select * into b from a where 1<>1 )z/+!y
法二:select top 0 * into b from a P {x`eD0
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) GqXnOmk
insert into b(a, b, c) select d,e,f from b; {H+~4XG
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) >;eWgQ6V
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 aU,Zjm7fp
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. (c ?OcwTH
4、说明:子查询(表名1:a 表名2:b) ^[noGjy
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 84UH&
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5、说明:显示文章、提交人和最后回复时间 G};os+FxF
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b _\YBB=Os
6、说明:外连接查询(表名1:a 表名2:b) 66*/"dBwm
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 0b9;vlGq$
7、说明:在线视图查询(表名1:a ) PpD ?TAlA
select * from (SELECT a,b,c FROM a) T where t.a > 1; nc#}-}`5
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 s
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select * from table1 where time between time1 and time2 Amf
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select a,b,c, from table1 where a not between 数值1 and 数值2 t@[&8j2B>
9、说明:in 的使用方法 D.zEE-cGyb
select * from table1 where a [not] in ('值1','值2','值4','值6') Vv4w?K
10、说明:两张关联表,删除主表中已经在副表中没有的信息 k/A8|
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 4k5X'&Q
11、说明:四表联查问题: _jOu`1w
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 ..... Ah,X?0+
12、说明:日程安排提前五分钟提醒 GsG.9nd
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 !rzbm&@
13、说明:一条sql 语句搞定数据库分页 /s"mqBXCG
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 &FF%VUfQJ
14、说明:前10条记录 96UL](l(`
select top 10 * form table1 where 范围
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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>!zZ
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) =*7K_M&
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 {<{
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(select a from tableA ) except (select a from tableB) except (select a from tableC) !63p?Q=
17、说明:随机取出10条数据 tLXwszR0r
select top 10 * from tablename order by newid() JsohhkJNGi
18、说明:随机选择记录 C?jk#T
select newid() >58N P1[k
19、说明:删除重复记录 j+He8w-4
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) pj:s+7"t
20、说明:列出数据库里所有的表名 4}@J]_]Z
select name from sysobjects where type='U' wQ
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21、说明:列出表里的所有的 'thWo wE
select name from syscolumns where id=object_id('TableName') Gf'qPLK0
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。 5+*MqO>
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 ^'j? {@
显示结果: ]n9o=^q/
type vender pcs A)9OkLrc
电脑 A 1 o!W
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电脑 A 1 ol QT r
光盘 B 2 6%bZZTP`
光盘 A 2 v?e@`;-
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手机 B 3 fgrflW$
手机 C 3 wVU.j$+_#
23、说明:初始化表table1 xj8yQ Y1
TRUNCATE TABLE table1 EXDZehLD<]
24、说明:选择从10到15的记录 .)L%ANf
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc \c1u$'| v
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三、技巧 }71a3EUK
1、1=1,1=2的使用,在SQL语句组合时用的较多 \ng!qN
"where 1=1" 是表示选择全部 "where 1=2"全部不选, `}t<5_
如: qxKW%{6o
if @strWhere !='' {j$ :9 H
begin
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere [B<htD&
end 0c6b_%Rd
else KE>|,Ur
begin v_M-:e3`
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' xQLVFgd
end nn[OC=cDN
我们可以直接写成 ?=zF]J:G1w
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere A[W3.$s
2、收缩数据库 h9<*+T
--重建索引 6Ih8~Hu
DBCC REINDEX g{|F<2rd[m
DBCC INDEXDEFRAG \4$V;C/n,
--收缩数据和日志 Kvx~2ZMx6
DBCC SHRINKDB .nDB{@#
DBCC SHRINKFILE KrVP#|9%"
3、压缩数据库 og0su
dbcc shrinkdatabase(dbname) \ZNUt$\
4、转移数据库给新用户以已存在用户权限 yW3!V-iA
exec sp_change_users_login 'update_one','newname','oldname' RuyqB>[o
go 'W'['TV
5、检查备份集 9)P-<
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' :wWPEhK
6、修复数据库 lICpfcc(+
ALTER DATABASE [dvbbs] SET SINGLE_USER `"@Pr,L
GO l9Xz,H
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK MTI[Mez
GO 'M20v-[
ALTER DATABASE [dvbbs] SET MULTI_USER TS2zzYE6Z
GO ;iA6[uz
7、日志清除 ) W,tL*9[
SET NOCOUNT ON m9~cQ!m
DECLARE @LogicalFileName sysname, 6:\0=k5
@MaxMinutes INT, PB[Y^q
@NewSize INT a -[:RJW
USE tablename -- 要操作的数据库名 !*I0}I
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 )gNS%tc*K
@MaxMinutes = 10, -- Limit on time allowed to wrap log. h"#[{$(
@NewSize = 1 -- 你想设定的日志文件的大小(M) LDX>S*cL
-- Setup / initialize 1u `{yl*+?
DECLARE @OriginalSize int +\s32o
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SELECT @OriginalSize = size 6gr?#D -F
FROM sysfiles MS Qz,nn
WHERE name = @LogicalFileName {>EM=ZZfg
SELECT 'Original Size of ' + db_name() + ' LOG is ' + RaT.%:CRm
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + M~h^~:Lk
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' :~"Dwrui
FROM sysfiles O@9<7@h+Nl
WHERE name = @LogicalFileName oItEGJ|
CREATE TABLE DummyTrans P5?M"j0/^
(DummyColumn char (8000) not null) M\m6|P
DECLARE @Counter INT, ?aMd#.&
@StartTime DATETIME, Z'Uc}M'U
@TruncLog VARCHAR(255) %"yy8~|
SELECT @StartTime = GETDATE(), i!yu%>:M
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ]h3{MTr/
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Nbyc,a[o
EXEC (@TruncLog) xZ=6
-- Wrap the log if necessary. 0,{tBo
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired "pA24Ze
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) yb/v?q?Fk
AND (@OriginalSize * 8 /1024) > @NewSize TyGsSc
BEGIN -- Outer loop. %f-Uwq&}Y"
SELECT @Counter = 0 {zNFp#z
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) vx7wW<e%D
BEGIN -- update "aT"o
INSERT DummyTrans VALUES ('Fill Log') tKP
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DELETE DummyTrans oS0rP'V^
SELECT @Counter = @Counter + 1 _6Z}_SiOl
END P#j>hS
EXEC (@TruncLog) o],z/MPL
END c.?+rcnq
SELECT 'Final Size of ' + db_name() + ' LOG is ' + >Hd Pcsl L
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + sjW;Nsp
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' sUe<21:
FROM sysfiles ]r&dWF
WHERE name = @LogicalFileName paYvYK-K?
DROP TABLE DummyTrans WHk rd8
SET NOCOUNT OFF w~a_FGYX
8、说明:更改某个表 iJaA&z5sr
exec sp_changeobjectowner 'tablename','dbo' n/
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9、存储更改全部表 7eU|iDYo
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ^630%YO
@OldOwner as NVARCHAR(128), (?ofL|Cg(
@NewOwner as NVARCHAR(128) CqAv^n7 }
AS O!3`^_.
DECLARE @Name as NVARCHAR(128) >|W\8dTQ
DECLARE @Owner as NVARCHAR(128) .ng:Z7
DECLARE @OwnerName as NVARCHAR(128) $`'%1;y@
DECLARE curObject CURSOR FOR Ld4Jp`Zg
select 'Name' = name, b%_[\((
'Owner' = user_name(uid) +Rq7m]
from sysobjects "k>;K,:
where user_name(uid)=@OldOwner X/AA8QV o
order by name vVfIe5+OP
OPEN curObject -.
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FETCH NEXT FROM curObject INTO @Name, @Owner 2;`F`}BA
WHILE(@@FETCH_STATUS=0) \L]T|]}(
BEGIN y%Wbm&h
if @Owner=@OldOwner
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begin #U?=D/
set @OwnerName = @OldOwner + '.' + rtrim(@Name) nq,P.~l
exec sp_changeobjectowner @OwnerName, @NewOwner d>bS)
end wM0P#+bA\
-- select @name,@NewOwner,@OldOwner L9bIdiB7
FETCH NEXT FROM curObject INTO @Name, @Owner r>kDRIHB
END Kc#42C;t/
close curObject IzWS6!zKU
deallocate curObject oc0z1u
GO LVAnZ'h/|
10、SQL SERVER中直接循环写入数据 iJ%`ym4Y
declare @i int hcrx(oJ5
set @i=1 w=}R'O;k
while @i<30 PvkHlb^x%
begin 4+2hj*I
insert into test (userid) values(@i) G
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set @i=@i+1 IA(+}V
end A1kqWhg\
小记存储过程中经常用到的本周,本月,本年函数 l
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Dateadd(wk,datediff(wk,0,getdate()),-1) 2nv-/%]
Dateadd(wk,datediff(wk,0,getdate()),6) #Py\'
Dateadd(mm,datediff(mm,0,getdate()),0) y^tp^
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) \?K>~{)
Dateadd(yy,datediff(yy,0,getdate()),0) R)u ${
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ?]Z EK8c
上面的SQL代码只是一个时间段 ?cmv;KV
Dateadd(wk,datediff(wk,0,getdate()),-1) F qH@iZ
Dateadd(wk,datediff(wk,0,getdate()),6) zrazFI0G
就是表示本周时间段. Z:kX9vw.
下面的SQL的条件部分,就是查询时间段在本周范围内的: se^(1R k
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) *p>1s!i
而在存储过程中 vkg."G:=
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) L\/YS;Y
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) =k|hH~