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。 PZDj)x_%B&
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一、基础 .+'`A"$8
1、说明:创建数据库 ')8c
CREATE DATABASE database-name '4L0=G:A<q
2、说明:删除数据库 me7?
drop database dbname CXZO
3、说明:备份sql server 5c W2
--- 创建 备份数据的 device "i}?jf
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USE master BfcpB)N&.K
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' _I&];WM\
--- 开始 备份 w,<nH:~
BACKUP DATABASE pubs TO testBack xux
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4、说明:创建新表 bK7j"
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) sI7<rI.t){
根据已有的表创建新表: K)z!e;r
A:create table tab_new like tab_old (使用旧表创建新表) R`_RcHY:
B:create table tab_new as select col1,col2... from tab_old definition only YCWt%a*I'
5、说明:删除新表 {NS6y \,
drop table tabname 78iu<L+If
6、说明:增加一个列 5$(qnOi
Alter table tabname add column col type ncGg@$E
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 :dZq!1~t
7、说明:添加主键: Alter table tabname add primary key(col) +8rGStv
说明:删除主键: Alter table tabname drop primary key(col) ";&5@H|
8、说明:创建索引:create [unique] index idxname on tabname(col....) \KGi54&Y
删除索引:drop index idxname sI@y)z
注:索引是不可更改的,想更改必须删除重新建。 3Pj 6(cf
9、说明:创建视图:create view viewname as select statement A`Nk gVq5:
删除视图:drop view viewname :z^VI M
10、说明:几个简单的基本的sql语句 sn4wd:b7%
选择:select * from table1 where 范围 d^0vaX6e}
插入:insert into table1(field1,field2) values(value1,value2) 6eUM[C.
删除:delete from table1 where 范围 7u9]BhcFv?
更新:update table1 set field1=value1 where 范围 M_5$y)M
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! #`1@4,iC
排序:select * from table1 order by field1,field2 [desc] sbxOnwP\
总数:select count as totalcount from table1 tML[~AZh
求和:select sum(field1) as sumvalue from table1 #i8] f{
平均:select avg(field1) as avgvalue from table1 K%+[2Hj2
最大:select max(field1) as maxvalue from table1 q13bV
最小:select min(field1) as minvalue from table1 8:x{
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11、说明:几个高级查询运算词 C6$F.v
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A: UNION 运算符 JD Q7
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。 Wsz-#kc\[
B: EXCEPT 运算符 E3):8>R;1
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。 N3_rqRd^
C: INTERSECT 运算符 ]dx6E6A,
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。 OwdA6it^f
注:使用运算词的几个查询结果行必须是一致的。 B.e3IM0
12、说明:使用外连接 3C+!Y#F
A、left outer join: qqmhh_[T
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。 G,VTFM6
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 Qx
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B:right outer join: 0Y%u[i/
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。 r34q9NFT5
C:full outer join: )2Ru}
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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。 $P9'"a)Lm
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二、提升 _y,?Cj=u|
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Nq$Xe~,*
法一:select * into b from a where 1<>1 q_h=O1W
法二:select top 0 * into b from a @w%{yzr%
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) @w8MOT$
insert into b(a, b, c) select d,e,f from b; zlUXp0W
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) n<}t\<LG^c
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 1Qc>A8SU
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 2|LgUA?<
4、说明:子查询(表名1:a 表名2:b) Ewfzjc
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) j9V*f
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5、说明:显示文章、提交人和最后回复时间 kw%vO6"q(
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b aBBTcN%'
6、说明:外连接查询(表名1:a 表名2:b) }mZsK>
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c F5hOKUjv
7、说明:在线视图查询(表名1:a ) NrHh(:
select * from (SELECT a,b,c FROM a) T where t.a > 1; H pZD^h?L
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 MJ=(rp=YU9
select * from table1 where time between time1 and time2 ]M:=\h,t>
select a,b,c, from table1 where a not between 数值1 and 数值2 Sk~( t
9、说明:in 的使用方法 0Gq}x;8H&
select * from table1 where a [not] in ('值1','值2','值4','值6') 1>KZ1Kf
10、说明:两张关联表,删除主表中已经在副表中没有的信息 h{J=Rq
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) aSN"MTw.
11、说明:四表联查问题: dx/NY1
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 ..... yF~iVt
12、说明:日程安排提前五分钟提醒 6N6}3J5
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 qu}&4_`%:V
13、说明:一条sql 语句搞定数据库分页 4
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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 3 NLC~CJ
14、说明:前10条记录 W)RCo}f
select top 10 * form table1 where 范围 G2
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.) >ZE8EL
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) <~rf;2LZ
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 /2<1/[#
(select a from tableA ) except (select a from tableB) except (select a from tableC) da'7*
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17、说明:随机取出10条数据 ,KfBG<3
select top 10 * from tablename order by newid() dbmty|d
18、说明:随机选择记录 Y&G]M
select newid() \Q
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19、说明:删除重复记录 <b5J"i&m
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 4v=NmO}
20、说明:列出数据库里所有的表名 \Y>!vh X
select name from sysobjects where type='U' 3I" <\M4x
21、说明:列出表里的所有的 yY3Mv/R
select name from syscolumns where id=object_id('TableName') l2AAEB_C.
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。 e=8z,.Xk
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 QJsud{ada
显示结果: |uT&M`7\{
type vender pcs +2ZBj6 e9
电脑 A 1 7QO QG:-
电脑 A 1 (_9cL,v
光盘 B 2 nVO|*Bnf)
光盘 A 2 @CxXkR
手机 B 3 e5"?ol0
手机 C 3 ^Hdru]A$2
23、说明:初始化表table1 &fIx2ZM[
TRUNCATE TABLE table1 kVH^(Pi
24、说明:选择从10到15的记录 r"%uP[H
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc UP8=V>T02
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三、技巧 w
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1、1=1,1=2的使用,在SQL语句组合时用的较多 Sh]g]xR
"where 1=1" 是表示选择全部 "where 1=2"全部不选, U1.w%b,
如: K;n5[o&c
if @strWhere !='' %Ob#GA+
begin TB8a#bK4
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Q9[$8
end .5t|FJ]`$
else "G(^v?x:P
begin _YT9zG
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 1]yjhw9g
end K4H U9!
我们可以直接写成 2E*k@
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere GWQ_X9+q
2、收缩数据库 ftw@ nQNU
--重建索引 #?V7kds]
DBCC REINDEX *<5zMSZO
DBCC INDEXDEFRAG Y!+q3`-%T
--收缩数据和日志 q%RPAe
DBCC SHRINKDB E&RiEhuv
DBCC SHRINKFILE uia[>&2
3、压缩数据库 3hPj;-u
dbcc shrinkdatabase(dbname) x'uxSeH$
4、转移数据库给新用户以已存在用户权限 M.[A%_|P
exec sp_change_users_login 'update_one','newname','oldname' r
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go PXH"%vVF
5、检查备份集 MV~-']2u
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' :'t+*{ff
6、修复数据库 iJr 1w&GL$
ALTER DATABASE [dvbbs] SET SINGLE_USER #U=}Pv~wM
GO =$^<@-;
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK LHS^[}x^1
GO 6{qI
ALTER DATABASE [dvbbs] SET MULTI_USER xpzQ"'be
GO Hy_}e"
7、日志清除 2".^Ma^D!
SET NOCOUNT ON clcj5=:
DECLARE @LogicalFileName sysname, 4)IRm2G
@MaxMinutes INT, %"1*,g{
@NewSize INT MmvMuX]#)
USE tablename -- 要操作的数据库名 (16U]s
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ?9?eA^X%
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 6?CBa]QG
@NewSize = 1 -- 你想设定的日志文件的大小(M) YXBU9T{r
-- Setup / initialize (Vvs:h%H
DECLARE @OriginalSize int Ep@NT+VnI
SELECT @OriginalSize = size //ZYN2lT4
FROM sysfiles z;74(5?q
WHERE name = @LogicalFileName I|{A&G}|q
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ZRjqjx
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 3=SN;cn
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' D+y_&+&,t
FROM sysfiles fuwv,[m
WHERE name = @LogicalFileName 8:iu 8c$
CREATE TABLE DummyTrans p-6(>,+E[
(DummyColumn char (8000) not null) EJbFo682
DECLARE @Counter INT, ,IODV`L
@StartTime DATETIME, IO(Y_7
@TruncLog VARCHAR(255) RyxEZ7dC<y
SELECT @StartTime = GETDATE(), ~MgU"P>
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' e/h2E dY
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ?;//%c8,.
EXEC (@TruncLog) TDMyZ!d
-- Wrap the log if necessary. WC?}a^
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 'A|OVyH
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) H,?)6pZ
AND (@OriginalSize * 8 /1024) > @NewSize 1VH$l(7IQ
BEGIN -- Outer loop. mJ>@Dh3>G
SELECT @Counter = 0 bhIyq4N
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) r%QnV0L^
BEGIN -- update U;QN+fF]u
INSERT DummyTrans VALUES ('Fill Log') CQLh;W`Dc
DELETE DummyTrans XO=UKk+EK
SELECT @Counter = @Counter + 1 R
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END @rTAbEk{U
EXEC (@TruncLog) @\!9dK-W
END icX$<lD
SELECT 'Final Size of ' + db_name() + ' LOG is ' + S b9In_*
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + e>ZF? (a0
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' h,D6MP
FROM sysfiles E2PMcT{)_
WHERE name = @LogicalFileName rQ4i %.
DROP TABLE DummyTrans y[}O(
SET NOCOUNT OFF pO~VI$7
8、说明:更改某个表 ^aW?0qsH
exec sp_changeobjectowner 'tablename','dbo' R]-$]koQO
9、存储更改全部表 NW$C1(oT
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ice7J2r_
@OldOwner as NVARCHAR(128), &|:T+LVv$+
@NewOwner as NVARCHAR(128) P p}N-me>_
AS Z1(-FT6O
DECLARE @Name as NVARCHAR(128) T@GR Tg
DECLARE @Owner as NVARCHAR(128) ic"n*SZa
DECLARE @OwnerName as NVARCHAR(128) Ul<'@A8
DECLARE curObject CURSOR FOR lu GEBPi
select 'Name' = name, )<6zbG
'Owner' = user_name(uid) lO+<T[
from sysobjects "/EE$eU
where user_name(uid)=@OldOwner *L%i-Wg"
order by name B>^5h?(lt
OPEN curObject +UK".
FETCH NEXT FROM curObject INTO @Name, @Owner Y'.WO[dgf
WHILE(@@FETCH_STATUS=0) K{
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BEGIN yxECK&&P0#
if @Owner=@OldOwner ) OqQz7'
begin -*?Y4}mK
set @OwnerName = @OldOwner + '.' + rtrim(@Name) I)$of9
exec sp_changeobjectowner @OwnerName, @NewOwner )P{I<TBI;
end .>(?c92
-- select @name,@NewOwner,@OldOwner 4LCgQS6
FETCH NEXT FROM curObject INTO @Name, @Owner A/ eZ!"Y
END HzO6hb{jJO
close curObject YzcuS/~x
deallocate curObject AX|-Gv
GO R|Oy/RGY$
10、SQL SERVER中直接循环写入数据 5 i1T?
declare @i int MuQBn7F{c
set @i=1 E0 nR Vg
while @i<30 V/0?0VKG
begin 8e'0AI_>
insert into test (userid) values(@i) >!j= {hK
set @i=@i+1 W~1/vJ.*l
end m_%1IJ
小记存储过程中经常用到的本周,本月,本年函数 n0X_m@
Dateadd(wk,datediff(wk,0,getdate()),-1) s[yIvlHw`
Dateadd(wk,datediff(wk,0,getdate()),6) u@`)u#
Dateadd(mm,datediff(mm,0,getdate()),0) cx]O#b6B.
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ZKGS?z
Dateadd(yy,datediff(yy,0,getdate()),0) CS 7"mE`{
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) -DO*,Eecv
上面的SQL代码只是一个时间段 w"CcWng1
Dateadd(wk,datediff(wk,0,getdate()),-1) ~3{C&c
Dateadd(wk,datediff(wk,0,getdate()),6) I#Q
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就是表示本周时间段. K8dlECy
下面的SQL的条件部分,就是查询时间段在本周范围内的: ZCQ7xQD
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) CI+dIv>
而在存储过程中 w8t,?dY
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 4>4*4!KR}
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) lu^c^p;