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。 Q~!hr0
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一、基础 3C[4!>|
1、说明:创建数据库 n(xlad
CREATE DATABASE database-name _ rVX_
2、说明:删除数据库 {^MAdC_
drop database dbname xKzFrP;/{
3、说明:备份sql server 5T3>fw2G
--- 创建 备份数据的 device t%B!\]
USE master >d
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Vzm+Ew
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--- 开始 备份 h`rjD d
BACKUP DATABASE pubs TO testBack KrG6z#)Uz
4、说明:创建新表 |5B9tjJ"
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Y8{1?LO
根据已有的表创建新表: TaJn2cC^
A:create table tab_new like tab_old (使用旧表创建新表) na:^7:I
B:create table tab_new as select col1,col2... from tab_old definition only $<mL2$.L~
5、说明:删除新表 |aJ6363f.
drop table tabname N;pr:
6、说明:增加一个列 H{zuIN/.1
Alter table tabname add column col type W2Z]?l;vQQ
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。 0BE^qe
7、说明:添加主键: Alter table tabname add primary key(col) ByvqwJY
说明:删除主键: Alter table tabname drop primary key(col) Y[?Wt/O;
8、说明:创建索引:create [unique] index idxname on tabname(col....) z9O/MHT[w
删除索引:drop index idxname |Z|xM
注:索引是不可更改的,想更改必须删除重新建。 tg3JU\
9、说明:创建视图:create view viewname as select statement O t<%gj;^
删除视图:drop view viewname 0)a?W,+O
10、说明:几个简单的基本的sql语句 o`! :Q!+
选择:select * from table1 where 范围 Fe<
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插入:insert into table1(field1,field2) values(value1,value2) ; 2-kQK9
删除:delete from table1 where 范围 Q&Ahr
更新:update table1 set field1=value1 where 范围 e`1s[ ^B
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ^O*hs%eO%
排序:select * from table1 order by field1,field2 [desc] Qug'B
总数:select count as totalcount from table1 >&Q. .`q
求和:select sum(field1) as sumvalue from table1 1)Bi>X
平均:select avg(field1) as avgvalue from table1 :.df( 1(RL
最大:select max(field1) as maxvalue from table1 me^Gk/`Em
最小:select min(field1) as minvalue from table1 Vho0f<`E
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11、说明:几个高级查询运算词 CoXL;\
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A: UNION 运算符 G_4P)G3H
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。 =JH,RQ
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B: EXCEPT 运算符 wGX"R 5
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。 }"H900WE|
C: INTERSECT 运算符 )pa|uH+N
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。 1*b%C"C
注:使用运算词的几个查询结果行必须是一致的。 @??
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12、说明:使用外连接 O G}&%NgH
A、left outer join: tTp`e0L*m
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。 XhV"<&v
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 O#Hz5A5
B:right outer join: !iOu07<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。 4jro4B`
C:full outer join: )E2Lf]
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。 &r!>2$B\
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二、提升 boovCW
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) [_1G\z_iE
法一:select * into b from a where 1<>1 kO4~N-&
法二:select top 0 * into b from a ^
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) !
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insert into b(a, b, c) select d,e,f from b; @$G
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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) %&(\dt&R1h
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 '#6DI"vJ
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. z#
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4、说明:子查询(表名1:a 表名2:b) kA`qExw%
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) d^^>3L!h
5、说明:显示文章、提交人和最后回复时间 Lr&BZM
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b -;z\BW5y
6、说明:外连接查询(表名1:a 表名2:b) dUSuhT
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 5L#M7E
7、说明:在线视图查询(表名1:a ) U6PUt'Kk@
select * from (SELECT a,b,c FROM a) T where t.a > 1; '|R|7nQAj
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 a9Rh
select * from table1 where time between time1 and time2 M!'tD!NWc
select a,b,c, from table1 where a not between 数值1 and 数值2 I =pd jD
9、说明:in 的使用方法 -H]O&u3'c
select * from table1 where a [not] in ('值1','值2','值4','值6') M
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 uGWk(qn
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) =&GV\ju
11、说明:四表联查问题: W#\4"'=I
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 ..... 3I(H.u
12、说明:日程安排提前五分钟提醒 sOmYQ{R
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 )dcGV$4t[
13、说明:一条sql 语句搞定数据库分页 v8N1fuP}
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 DLZ63'
14、说明:前10条记录 6}2Lt[>O
select top 10 * form table1 where 范围 $=R\3:j
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) 8/v_ uEG
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 2Y{9Df
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 !>j-j
(select a from tableA ) except (select a from tableB) except (select a from tableC) SfT ]C~#$N
17、说明:随机取出10条数据 0IuU4h5Fr
select top 10 * from tablename order by newid() ly+7klQ;.
18、说明:随机选择记录 B4=gMVp1
select newid() m%puD9
19、说明:删除重复记录 6m&I_icM
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) :Fl: bRH+
20、说明:列出数据库里所有的表名 (fS4qz:&l
select name from sysobjects where type='U' _`58G#z
21、说明:列出表里的所有的 tnntHQ&b
select name from syscolumns where id=object_id('TableName') 4V5*6O9(u
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。 5Z{[.&x
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 Ycm1 _z
显示结果: u05O[>w
type vender pcs 1|CO>)*D
电脑 A 1 je\UfEo%
电脑 A 1 YQJ_t@0C
光盘 B 2 []NAV
光盘 A 2 s!Vtwp9
手机 B 3 V,}cDT>
手机 C 3 i8F~$6C
23、说明:初始化表table1 1'U-n{fD
TRUNCATE TABLE table1 :+n7oOV
24、说明:选择从10到15的记录 .w&Z=YM
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ?##GY;#
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三、技巧 'yqp
1、1=1,1=2的使用,在SQL语句组合时用的较多 Lm/^ 8V+
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ~ nIZg5
如: ezeGw?/
if @strWhere !='' '1aOdEZA*
begin 0vEa]ljS
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere h 9/68Gc?6
end yL1\V7GI{[
else O;r8l+
begin 5k @k
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' F7df
end 0@KBQv"v
我们可以直接写成 .KV?;{~q@
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere k<y$[xV
2、收缩数据库 ?*g]27f11
--重建索引 'tc$#f^:
DBCC REINDEX $xqphhBg
DBCC INDEXDEFRAG F-t-d1w6
--收缩数据和日志 P`0aU3pl
DBCC SHRINKDB Z(FAQ\7
DBCC SHRINKFILE >r3Wo%F'
3、压缩数据库 3ul
dbcc shrinkdatabase(dbname) {^v50d
4、转移数据库给新用户以已存在用户权限 ^H>vJT
exec sp_change_users_login 'update_one','newname','oldname' r mhB!Lo
go ;X>KP,/r$
5、检查备份集 u:k#1Nn!
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Ty5\zxC|
6、修复数据库 &' Ch[Wo]H
ALTER DATABASE [dvbbs] SET SINGLE_USER XyhdsH5%3!
GO ~lMsD~$sO
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK rYT3oqpfT
GO {=kA8U
ALTER DATABASE [dvbbs] SET MULTI_USER ITTC}
GO !&X}?NK
7、日志清除 L/shF}<
SET NOCOUNT ON CUoMB r
DECLARE @LogicalFileName sysname, nt7ui*k
@MaxMinutes INT, sfH|sp
@NewSize INT 0&Qn7L
USE tablename -- 要操作的数据库名 ($-o"y"x
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ?tBEB5
@MaxMinutes = 10, -- Limit on time allowed to wrap log. |tmD`ndO
@NewSize = 1 -- 你想设定的日志文件的大小(M) NWf!c-':
-- Setup / initialize p?%G|Q
DECLARE @OriginalSize int @|M10r9E
SELECT @OriginalSize = size G$q=WM!%#s
FROM sysfiles H7WKnn@
WHERE name = @LogicalFileName (mycUU%
SELECT 'Original Size of ' + db_name() + ' LOG is ' + RNPqW,B!0
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 6w5 4+n
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ,]+6kf 5
FROM sysfiles SFuzH)+VO
WHERE name = @LogicalFileName E~24b0<7
CREATE TABLE DummyTrans X|b~,X%N
(DummyColumn char (8000) not null) FT=w`NE,+
DECLARE @Counter INT, StE4n0V
@StartTime DATETIME, VF4F7'
@TruncLog VARCHAR(255) ks!
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SELECT @StartTime = GETDATE(), Z0x N9S
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' :f`1
DBCC SHRINKFILE (@LogicalFileName, @NewSize) *l|CrUa
EXEC (@TruncLog) #fwG~Q(
-- Wrap the log if necessary. Ts^IA67&<
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired H|Eu,eq-E
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) _3`{wzMA
AND (@OriginalSize * 8 /1024) > @NewSize b2z~C{l
BEGIN -- Outer loop. ";Lpf]<
SELECT @Counter = 0 he/FtkU
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) :R_(+EK1
BEGIN -- update
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INSERT DummyTrans VALUES ('Fill Log') 3ZC[H'|
DELETE DummyTrans 7;Wj ^#
SELECT @Counter = @Counter + 1 \jC}>9
END U,/>p=s
EXEC (@TruncLog) yNO5h]o
END LJT+tb?K
SELECT 'Final Size of ' + db_name() + ' LOG is ' + >%xJ e'
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + J^u8d?>r
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' @o8\`G
FROM sysfiles .L8S_Mz
WHERE name = @LogicalFileName _m@QeO'yh
DROP TABLE DummyTrans K'y;j~`-
SET NOCOUNT OFF :.@gd7T
8、说明:更改某个表 $g*|h G/{
exec sp_changeobjectowner 'tablename','dbo' l("_JI
9、存储更改全部表 R#gip
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch )wAqaG_d
@OldOwner as NVARCHAR(128), x3]es"4Q
@NewOwner as NVARCHAR(128) aRR*<dY
AS zK33.HY
DECLARE @Name as NVARCHAR(128) #b:8-Lt:M
DECLARE @Owner as NVARCHAR(128) kz+P?mopm
DECLARE @OwnerName as NVARCHAR(128) TfMuQ i'>
DECLARE curObject CURSOR FOR op[5]tjL
select 'Name' = name, KyDQ<Dq&
'Owner' = user_name(uid) \4mw>8wA
from sysobjects sz_|py?0
where user_name(uid)=@OldOwner `_<K#AG Ai
order by name V\Rbnvq
OPEN curObject >0{{loqq
FETCH NEXT FROM curObject INTO @Name, @Owner T-eeYw?Yf
WHILE(@@FETCH_STATUS=0) Cdc6<8
BEGIN 1}9@aKM
if @Owner=@OldOwner dqnxhN+&
begin S=2-<R
set @OwnerName = @OldOwner + '.' + rtrim(@Name) fk9FR^u
exec sp_changeobjectowner @OwnerName, @NewOwner 9"oc.ue.2D
end Wl}d6ZTm
-- select @name,@NewOwner,@OldOwner ~c+0SuJ
FETCH NEXT FROM curObject INTO @Name, @Owner J
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END {3'z}q
close curObject _"=Y j3?G%
deallocate curObject x?T/=C
GO 1)vdM(y3j
10、SQL SERVER中直接循环写入数据 wS#.Wzp.w
declare @i int *s<FE F
set @i=1 !|hv49!H
while @i<30 2?#IwT'
begin na_Y<R`
insert into test (userid) values(@i) }h>QkV,{2
set @i=@i+1 pGh2 4E
end /wVrr%SN
小记存储过程中经常用到的本周,本月,本年函数 ?$v#;n?@I
Dateadd(wk,datediff(wk,0,getdate()),-1) h`,dg%J*B
Dateadd(wk,datediff(wk,0,getdate()),6) [<7Hy,xr_
Dateadd(mm,datediff(mm,0,getdate()),0) cOq^}Ohan
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) _da>=^hFJ
Dateadd(yy,datediff(yy,0,getdate()),0) k~h'`(
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) A2!7a}*1(
上面的SQL代码只是一个时间段 \-gZ_>)
Dateadd(wk,datediff(wk,0,getdate()),-1) 1W;q(#q
Dateadd(wk,datediff(wk,0,getdate()),6) `A])4q$
就是表示本周时间段. j!xt&t4D
下面的SQL的条件部分,就是查询时间段在本周范围内的: 1 f).J
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Q&rpW:^v
而在存储过程中 `XS6t)!ik
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) \|R P-8
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) LS*^TA(I[