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。 EKd3$(^
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一、基础 "gvw0)
1、说明:创建数据库 h @,e`Z
CREATE DATABASE database-name IO!1|JMr6
2、说明:删除数据库 )=E~CpKV
drop database dbname NC.P2^%
3、说明:备份sql server QYTTP6 Gz+
--- 创建 备份数据的 device yEUNkZ5^
USE master PWk?8dL-
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ]6BmCh
--- 开始 备份 *Qg5Z
BACKUP DATABASE pubs TO testBack ZE8/ m")
4、说明:创建新表 &[ u6oAR
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) X`3vSCn
根据已有的表创建新表: B>|U-[A
A:create table tab_new like tab_old (使用旧表创建新表) 8gbm "!
B:create table tab_new as select col1,col2... from tab_old definition only B3>Uba*-)}
5、说明:删除新表 \l]pe|0EW
drop table tabname 'y6!%k*
6、说明:增加一个列 {y&\?'L'
Alter table tabname add column col type a()6bRc~T
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 BgkB x
7、说明:添加主键: Alter table tabname add primary key(col) {Bq"$M!Y
说明:删除主键: Alter table tabname drop primary key(col) Oh/b?|imG
8、说明:创建索引:create [unique] index idxname on tabname(col....) :q>oD-b$}
删除索引:drop index idxname ik Y]8BCc
注:索引是不可更改的,想更改必须删除重新建。 iRUR4Zs
9、说明:创建视图:create view viewname as select statement C~KWH@
删除视图:drop view viewname xQ#Akd=
10、说明:几个简单的基本的sql语句 (9KDtr*(2i
选择:select * from table1 where 范围 =(.mf
插入:insert into table1(field1,field2) values(value1,value2) Rnj Jg?I=
删除:delete from table1 where 范围 5fegWCJ
更新:update table1 set field1=value1 where 范围 -4vHK!l
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! YBtq0c
排序:select * from table1 order by field1,field2 [desc] "y~muE:.
总数:select count as totalcount from table1 "$W|/vD+
求和:select sum(field1) as sumvalue from table1 q:
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平均:select avg(field1) as avgvalue from table1 b=K6IX;
最大:select max(field1) as maxvalue from table1 9iGE`1N%E
最小:select min(field1) as minvalue from table1 Ld\LKwo
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11、说明:几个高级查询运算词 c?.r"5#
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A: UNION 运算符 <+T\F;
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。 Z6IJ o%s
B: EXCEPT 运算符 lrs0^@.+
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。 d2C[wQF
C: INTERSECT 运算符 }fJ:wku
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。 rnn2u+OG
注:使用运算词的几个查询结果行必须是一致的。 {d 1N&
12、说明:使用外连接 QiTR-M2C!
A、left outer join: abROFI5.L
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。 $u; >hk
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c R3B5-^s
B:right outer join: `26V`%bPkr
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 0'yG1qG
C:full outer join: S,*{q(
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 NK7H,V}T
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二、提升 sf |oNOz
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) YN,y0t/cQ
法一:select * into b from a where 1<>1 vzY'+9q1.
法二:select top 0 * into b from a ]aC':55(
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) %[]"QbF?
insert into b(a, b, c) select d,e,f from b; oLrkOn/aY
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) UAsF0&]
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 MAE7A"la
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. {D_++^
4、说明:子查询(表名1:a 表名2:b) xSpMyXrQ
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) g08*}0-k
5、说明:显示文章、提交人和最后回复时间 qri}=du&F
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b
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6、说明:外连接查询(表名1:a 表名2:b) @Jb@L
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Rk($lW)
7、说明:在线视图查询(表名1:a ) zmrQf/y{R
select * from (SELECT a,b,c FROM a) T where t.a > 1; Js\-['`
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 Q`.'-iq
select * from table1 where time between time1 and time2 )XLj[6j0
select a,b,c, from table1 where a not between 数值1 and 数值2 `zdH1 p^w
9、说明:in 的使用方法 N]1V1c$G*
select * from table1 where a [not] in ('值1','值2','值4','值6') 1YOg1 n+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 $}qDV>
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) %f3c7\=C
11、说明:四表联查问题: dT5J-70Fl
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... .S~@BI(|<
12、说明:日程安排提前五分钟提醒 L;/9L[s,
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 LP.HS'M~u
13、说明:一条sql 语句搞定数据库分页 Sm$p\ORa
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 h5L=M^z!>
14、说明:前10条记录 !]$V9F{K
select top 10 * form table1 where 范围 WGH%92
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) y;Qy"-)qb
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) D:=t*2-Iv
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 )l`1)Ea~
(select a from tableA ) except (select a from tableB) except (select a from tableC) 't
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17、说明:随机取出10条数据 r_b8,I6{]
select top 10 * from tablename order by newid() v6wRME;JA
18、说明:随机选择记录 JB&G~7Q85
select newid() y,MPGW_
19、说明:删除重复记录 <RhOjZgyZ
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) F(#ha J$>
20、说明:列出数据库里所有的表名 EkN_8(w
select name from sysobjects where type='U' OENzG~
21、说明:列出表里的所有的 Y\.-v\uJu
select name from syscolumns where id=object_id('TableName') r?fH
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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。 FoE|Js
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@<Pu@?xm
显示结果: :lUX5j3
type vender pcs T>d\%*Q+B
电脑 A 1 C">`' G2
电脑 A 1 hHcJN
光盘 B 2 P+[QI
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光盘 A 2 TqIAWbb&
手机 B 3 "gFxfWIA
手机 C 3 s(Z(e %
23、说明:初始化表table1 hT?6sWa
TRUNCATE TABLE table1 +T9Q_e*
24、说明:选择从10到15的记录 eymi2-a<
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ? m&IF<b
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三、技巧 r]v&t
1、1=1,1=2的使用,在SQL语句组合时用的较多 &=YSM.G
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Yl$X3wi
如: m;dm|4L^
if @strWhere !='' Sa L"!uAk
begin +}P%HH]E/p
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere $0_^=DEW
end &,J*_F<s2<
else M|d={o9Hp
begin djWcbC=g_
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' )D;*DUtMVm
end ~e{H#*f&1/
我们可以直接写成 Rq) 0i}F
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere d^PD#&"g
2、收缩数据库 :4|M
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--重建索引 S@x}QQ|.
DBCC REINDEX UEzsDJu
DBCC INDEXDEFRAG C;9t">prk
--收缩数据和日志 X2qv^G,
DBCC SHRINKDB C\7u<2c
DBCC SHRINKFILE ~8TF*3[}[
3、压缩数据库 sI'a1$
dbcc shrinkdatabase(dbname) D}-o+6TI?
4、转移数据库给新用户以已存在用户权限 %;7.9%
exec sp_change_users_login 'update_one','newname','oldname' z5'ZN+
go k}GjD2m
5、检查备份集 Y,C=@t@_
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Q
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6、修复数据库 y,Jh@n';|
ALTER DATABASE [dvbbs] SET SINGLE_USER k0L] R5W
GO %Uy%kN_&
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Y(_KizBY
GO P|N2R5(>T
ALTER DATABASE [dvbbs] SET MULTI_USER G8eD7%{b:)
GO zCt\o
7、日志清除 ?OE#q$ g
SET NOCOUNT ON um7o !yg,
DECLARE @LogicalFileName sysname, Ry&q1j
@MaxMinutes INT, )>\4ULR83
@NewSize INT !DPF7x(-{
USE tablename -- 要操作的数据库名 61} i5o
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 /t*YDWLg
@MaxMinutes = 10, -- Limit on time allowed to wrap log. `z9J`r=I
@NewSize = 1 -- 你想设定的日志文件的大小(M) #;]2=@
-- Setup / initialize :$?Q D
DECLARE @OriginalSize int wd/G|kNO
SELECT @OriginalSize = size `?"6l5d.]
FROM sysfiles fxd0e;NAAh
WHERE name = @LogicalFileName B8 H75sz
SELECT 'Original Size of ' + db_name() + ' LOG is ' + k^%2_H
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + {pWBwf>R C
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' vg)Z]F=t(
FROM sysfiles :=*}htP4C
WHERE name = @LogicalFileName KVN"XqE4
CREATE TABLE DummyTrans [[WF0q
(DummyColumn char (8000) not null) !;v.>.lw
DECLARE @Counter INT, OUI6
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@StartTime DATETIME, g\Ak;03n
@TruncLog VARCHAR(255) 9C/MRmv`
SELECT @StartTime = GETDATE(), v>H=,.`0\
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' D<bI2
DBCC SHRINKFILE (@LogicalFileName, @NewSize) G(/DtY]
EXEC (@TruncLog) %?9Ok
-- Wrap the log if necessary. z\T Lsx
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ^z~~VBv
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) +6l]] *H
AND (@OriginalSize * 8 /1024) > @NewSize H=p`T+
BEGIN -- Outer loop. -R0/o7
SELECT @Counter = 0 zT[6eZ8m
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) w^HjZV
BEGIN -- update Qqc]aVRF
INSERT DummyTrans VALUES ('Fill Log') O- #TZ
DELETE DummyTrans ?,)"~c$hZ
SELECT @Counter = @Counter + 1 XN#&NT{t}
END +BL{@,zr
EXEC (@TruncLog) $ J1f.YE
END -:<lkq&/
SELECT 'Final Size of ' + db_name() + ' LOG is ' + [|RjHGf
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + )K;]y-Us[
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' kccWoU,
FROM sysfiles irKIy
WHERE name = @LogicalFileName k_ Y~;P@
DROP TABLE DummyTrans Dz;HAyPj
SET NOCOUNT OFF \S4SI
8、说明:更改某个表 mrM4RoO
exec sp_changeobjectowner 'tablename','dbo' Qhn;`9+L
9、存储更改全部表 fvqd'2 t
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch T2=HG Z
@OldOwner as NVARCHAR(128), s_[VHPN
@NewOwner as NVARCHAR(128) DMn4ll|
AS $4m*kQ
DECLARE @Name as NVARCHAR(128) N|K4{Frm
DECLARE @Owner as NVARCHAR(128) uwmQ?LS]V
DECLARE @OwnerName as NVARCHAR(128) TTZe$>f
DECLARE curObject CURSOR FOR ~aTKG|74
select 'Name' = name, <jA105U"m>
'Owner' = user_name(uid) p?# pT}1
from sysobjects nlc.u}#
where user_name(uid)=@OldOwner -tLO.JK<
order by name
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OPEN curObject e,gyQjJR
FETCH NEXT FROM curObject INTO @Name, @Owner QJGKQ2^ n
WHILE(@@FETCH_STATUS=0) .c+9P<VmC}
BEGIN QkQ!Ep(
if @Owner=@OldOwner :Ht;0|[H
begin 28I^$> [
set @OwnerName = @OldOwner + '.' + rtrim(@Name) KpHw-6"
exec sp_changeobjectowner @OwnerName, @NewOwner BPv>$
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end cn`iX(ZgR
-- select @name,@NewOwner,@OldOwner !%)]56(
FETCH NEXT FROM curObject INTO @Name, @Owner 2g-` ]Vqb
END ny*i+4Mb
close curObject O.QK"pKD\
deallocate curObject FX}Gt=
GO ezm&]F`
10、SQL SERVER中直接循环写入数据 n3KI+I%nQ
declare @i int (xpn`NA
set @i=1 *O~e
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while @i<30 lDU_YEQ>
begin Um`!%
insert into test (userid) values(@i) W7sn+g\
set @i=@i+1 [?0d~Q(R#
end cU.9}-)
小记存储过程中经常用到的本周,本月,本年函数 pUYM}&dX
Dateadd(wk,datediff(wk,0,getdate()),-1) B?bW1
Dateadd(wk,datediff(wk,0,getdate()),6) >jg0s)RA'
Dateadd(mm,datediff(mm,0,getdate()),0) r!
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) |nUl\WRd\
Dateadd(yy,datediff(yy,0,getdate()),0) E_T2z4lw
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 3gEMRy*+
上面的SQL代码只是一个时间段 9=`W p6Gmn
Dateadd(wk,datediff(wk,0,getdate()),-1) p@
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Dateadd(wk,datediff(wk,0,getdate()),6) pzZk\-0R
就是表示本周时间段. #xh_
下面的SQL的条件部分,就是查询时间段在本周范围内的: q5DEw&UZJ
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) H`9Uf)
而在存储过程中 ~f\G68c
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) (p#0)C
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) D{8PQ2x>