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。 >5wx+n)/)
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一、基础 "7v-`i
1、说明:创建数据库 -!)xQvagD.
CREATE DATABASE database-name zh$}~RG[
2、说明:删除数据库 )I\=BPo|B
drop database dbname 87WBM;$&s
3、说明:备份sql server <jS~ WI@
--- 创建 备份数据的 device E0/mSm"(T
USE master nkv(~ej(
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' @VN&t:/ l
--- 开始 备份 O8]'o*<]
BACKUP DATABASE pubs TO testBack ?go:e#
4、说明:创建新表 uHIiH@S
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) DOz\n|8S
根据已有的表创建新表: A!vCb
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A:create table tab_new like tab_old (使用旧表创建新表) 63!rUB!
B:create table tab_new as select col1,col2... from tab_old definition only O'GG Ti]e
5、说明:删除新表 cV-1?h63
drop table tabname %Rh;=p`
6、说明:增加一个列 h C=:q
Alter table tabname add column col type 3@n>*7/E
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。 i-U4RZE
7、说明:添加主键: Alter table tabname add primary key(col)
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说明:删除主键: Alter table tabname drop primary key(col) E(Rh#+]Y5
8、说明:创建索引:create [unique] index idxname on tabname(col....) rtQHWRUn
删除索引:drop index idxname $^ 'aCU0C
注:索引是不可更改的,想更改必须删除重新建。 Ro=AADv@
9、说明:创建视图:create view viewname as select statement $hR)i
删除视图:drop view viewname ^+SkCO
10、说明:几个简单的基本的sql语句 O g%U
选择:select * from table1 where 范围 O8U<{jgAG
插入:insert into table1(field1,field2) values(value1,value2) )c/Fasfg[P
删除:delete from table1 where 范围 dP]1tAO,y
更新:update table1 set field1=value1 where 范围 .bD_R7Bi6
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ^O^:$nXhYy
排序:select * from table1 order by field1,field2 [desc] (!5LW'3B
总数:select count as totalcount from table1 QFPfIb/
求和:select sum(field1) as sumvalue from table1 CnN9!~]"
平均:select avg(field1) as avgvalue from table1 YYg)
最大:select max(field1) as maxvalue from table1 mqfO4"lt
最小:select min(field1) as minvalue from table1 r$wZt
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11、说明:几个高级查询运算词 JM.XH7k
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A: UNION 运算符 ;oH,~|K
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。 kJs^ z
B: EXCEPT 运算符 N"[B=fU}
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。 (/" &
C: INTERSECT 运算符 $mA5@O~C5\
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 P
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注:使用运算词的几个查询结果行必须是一致的。 P5QQpY{<I
12、说明:使用外连接 /"qcl7F
A、left outer join: 7yI@"c#O
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 FZpKFsPx
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c sTHq&(hLUG
B:right outer join: \'?#i@O
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 h7_)%U<J2
C:full outer join: ^b?2N/m@
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 O';ew)tI
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二、提升 ekf$dgoR
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 5iFV;W
法一:select * into b from a where 1<>1 Vs0 SXj
法二:select top 0 * into b from a K=u0nrG*
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ^DAa%u
insert into b(a, b, c) select d,e,f from b; \Mx
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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) w5~i^x
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 j,%EW+j$
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. h=RDO
4、说明:子查询(表名1:a 表名2:b) q(z7~:+qNr
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) IvBGpT"(I
5、说明:显示文章、提交人和最后回复时间 sJr5t?
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b X.|Ygx
6、说明:外连接查询(表名1:a 表名2:b) 3=4SGt5m
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c JSMPyj
7、说明:在线视图查询(表名1:a ) F#q&(
select * from (SELECT a,b,c FROM a) T where t.a > 1; \x\.
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 .5tg4%l
select * from table1 where time between time1 and time2 4B O %{
select a,b,c, from table1 where a not between 数值1 and 数值2 /-*hjX$n
9、说明:in 的使用方法 )q?$p9
select * from table1 where a [not] in ('值1','值2','值4','值6') ,I*X)(
10、说明:两张关联表,删除主表中已经在副表中没有的信息 U1m\\<,
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) \gKdDS
11、说明:四表联查问题: ?AsDk ~3
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 ..... oFg'wAO.
12、说明:日程安排提前五分钟提醒 pVokgUrC
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 8cr NOZS6
13、说明:一条sql 语句搞定数据库分页 [Z}B"
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 WVL#s?=g
14、说明:前10条记录 wa3F
select top 10 * form table1 where 范围 Sni=gZ K
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.) $iJnxqn
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) [ #]jC[
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 Sb<\-O14"
(select a from tableA ) except (select a from tableB) except (select a from tableC) LcUlc)YH5
17、说明:随机取出10条数据 ^e9aD9
select top 10 * from tablename order by newid() H@!#;w
18、说明:随机选择记录 co]Gmg6p
select newid() KRk~w]
19、说明:删除重复记录 VO9f~>`(
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) nP_=GI
20、说明:列出数据库里所有的表名 I6w/0,azC
select name from sysobjects where type='U' rF8
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21、说明:列出表里的所有的 {[3YJkrM
select name from syscolumns where id=object_id('TableName') (|0b7|'T
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 BMjfqX
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type rt.[,m
显示结果: .~<]HAwq
type vender pcs hAa[[%wPhU
电脑 A 1 _7 `E[&v
电脑 A 1 ,P{HE8.
光盘 B 2 Y+qus
光盘 A 2 DcU C,
手机 B 3 AF[>fMI
手机 C 3 h6FgS9H
23、说明:初始化表table1 cdp{W
TRUNCATE TABLE table1 2?1}ZXr
24、说明:选择从10到15的记录 hT=f;6$
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ~^7
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三、技巧 (,TH~("{
1、1=1,1=2的使用,在SQL语句组合时用的较多 G1r V<,#m
"where 1=1" 是表示选择全部 "where 1=2"全部不选, YAMfP8S
如: >W~=]&7{s4
if @strWhere !='' -7L
begin %#4 +!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere kpT>G$s~gy
end KDaN-r^{%
else G|V\^.f<
begin LH.%\TMN$
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' %%x0w^
end Q
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我们可以直接写成 ;r=?BbND?
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere .r*#OUC
2、收缩数据库 3 9yz~
--重建索引 |Ib.)
DBCC REINDEX EFv4=OWB
DBCC INDEXDEFRAG x {vIT- f
--收缩数据和日志 Xiw@
DBCC SHRINKDB lG
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DBCC SHRINKFILE vhNohCt
3、压缩数据库
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dbcc shrinkdatabase(dbname) 2i"HqAB
4、转移数据库给新用户以已存在用户权限 U~hCn+0
exec sp_change_users_login 'update_one','newname','oldname' GM77Z.Y
go V:QdQ;c
5、检查备份集 ^Bn1;
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ac3_L$X[
6、修复数据库 iU,/!IQ
ALTER DATABASE [dvbbs] SET SINGLE_USER ,=x
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GO 'me:Zd
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK `L;OY 4
GO N@}gLBf
ALTER DATABASE [dvbbs] SET MULTI_USER /xF 9:r
GO wU.'_SBfB
7、日志清除 "C& J wm?
SET NOCOUNT ON .2/,XwIr
DECLARE @LogicalFileName sysname, a.1`\$]d
@MaxMinutes INT, wyNC|P;j$g
@NewSize INT `{%-*f^
USE tablename -- 要操作的数据库名 s?5d
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 >Rr!rtc'x
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ;i/"$K
@NewSize = 1 -- 你想设定的日志文件的大小(M) +fkP+RVY
-- Setup / initialize .byc;9M%
DECLARE @OriginalSize int {GAsFnZk
SELECT @OriginalSize = size w}"!l G
FROM sysfiles l,^xX=,
WHERE name = @LogicalFileName j_(?=7Y3g
SELECT 'Original Size of ' + db_name() + ' LOG is ' + A}gYcc85Z
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + &bn*p.=G
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' /%-o.hT
FROM sysfiles xP42xv9U
WHERE name = @LogicalFileName Ls lM$
CREATE TABLE DummyTrans k"0%' Y
(DummyColumn char (8000) not null) _dJp
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DECLARE @Counter INT, cxL,]27Bu
@StartTime DATETIME, uF+);ig
@TruncLog VARCHAR(255) [2 =^C=52
SELECT @StartTime = GETDATE(), \f6lT3"VN
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' /j$$0F>s7
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Zp^)_ 0
EXEC (@TruncLog) mf+K{y,L
-- Wrap the log if necessary. is64)2F](
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 3&O% &
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) RA!x
AND (@OriginalSize * 8 /1024) > @NewSize vM5k4%D
BEGIN -- Outer loop. /DK*yS
SELECT @Counter = 0 /\6}SG;
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ^ b=5 6~[
BEGIN -- update
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INSERT DummyTrans VALUES ('Fill Log') n+v!H O"2u
DELETE DummyTrans MoZU(j
SELECT @Counter = @Counter + 1 E=$7ieW
END c`rfKr&z
EXEC (@TruncLog) kt;}]O2%R
END L~'^W/N
SELECT 'Final Size of ' + db_name() + ' LOG is ' + HJnv'^yn
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + wa9'2a1?
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' e{c._zr,
FROM sysfiles /%2:+w
WHERE name = @LogicalFileName kxcgOjrmI
DROP TABLE DummyTrans Uh<H*o6e 9
SET NOCOUNT OFF `HE>%=]b
8、说明:更改某个表 pE9aT5
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exec sp_changeobjectowner 'tablename','dbo' JrY"J]/
9、存储更改全部表 d,Im&j_Z
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch =e"H1^Ml
@OldOwner as NVARCHAR(128), V#n?&-{V
@NewOwner as NVARCHAR(128) |6\FI?
AS pZni,<Q
DECLARE @Name as NVARCHAR(128) }Bv30V2-(
DECLARE @Owner as NVARCHAR(128) ,Y78Q
DECLARE @OwnerName as NVARCHAR(128) S
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DECLARE curObject CURSOR FOR n_e}>1_
select 'Name' = name, |H3?ox*
'Owner' = user_name(uid) A>rW Go.{E
from sysobjects fRca"v V
where user_name(uid)=@OldOwner O=4ceEmz
order by name 8u7K$Q
OPEN curObject t-?KKU8
FETCH NEXT FROM curObject INTO @Name, @Owner =R"Eb1
WHILE(@@FETCH_STATUS=0) )'/nS$\E:
BEGIN p@!@^1j=
if @Owner=@OldOwner >*<6 zQf
begin USHlb#*
set @OwnerName = @OldOwner + '.' + rtrim(@Name) `\WcF7
exec sp_changeobjectowner @OwnerName, @NewOwner yhJA;&}>
end 'p|Iwtjn>
-- select @name,@NewOwner,@OldOwner \E ? iw.}
FETCH NEXT FROM curObject INTO @Name, @Owner O>tC]sm%
END R-2FNl
close curObject 5<:VJC<
deallocate curObject i_jax)m%
GO x):k#cu[L
10、SQL SERVER中直接循环写入数据 <MWXew7b
declare @i int S1x.pLHj8
set @i=1 6x (L&>F
while @i<30 TCEXa?,L
begin rhzv^t
insert into test (userid) values(@i) ~_# Y,)S!z
set @i=@i+1 tehI!->l
end yccuTQvz
小记存储过程中经常用到的本周,本月,本年函数 9FIe W[
Dateadd(wk,datediff(wk,0,getdate()),-1) S,)|~#5x
Dateadd(wk,datediff(wk,0,getdate()),6) c],frhmyd
Dateadd(mm,datediff(mm,0,getdate()),0) ="'P=Xh!8
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Gn2bZ%l
Dateadd(yy,datediff(yy,0,getdate()),0) ^!v}
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ?( dYW7S
上面的SQL代码只是一个时间段 "JQt#[9l
Dateadd(wk,datediff(wk,0,getdate()),-1) P!4{#'_}
Dateadd(wk,datediff(wk,0,getdate()),6) 4,*^QK
就是表示本周时间段. 7S~9E2N
下面的SQL的条件部分,就是查询时间段在本周范围内的: =p&'_a^$
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 8#d1}Y
而在存储过程中 #.<F5
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) mC[U)` ey
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) !7"K>m<