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。 b/g"ws_
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一、基础 *)H&n>"e
1、说明:创建数据库 Vn1hr;i]
CREATE DATABASE database-name Wr+1G 8
2、说明:删除数据库 RIQw+RG>
drop database dbname ,)JSXo
3、说明:备份sql server 2r~&+0sBP
--- 创建 备份数据的 device =-GHs$u%f
USE master N2_9V~!
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' YDMimis\H5
--- 开始 备份 Jxy94y*
BACKUP DATABASE pubs TO testBack b 7%O[
4、说明:创建新表 N>J"^ GX
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ~0~f
根据已有的表创建新表: m;]glAtt
A:create table tab_new like tab_old (使用旧表创建新表) ,J0BG0jB^u
B:create table tab_new as select col1,col2... from tab_old definition only wRi` L7
5、说明:删除新表 xHMbtY
drop table tabname K@PQLL#yJp
6、说明:增加一个列 (`&`vf
Alter table tabname add column col type xjDV1Xf*
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 U|HF;L
7、说明:添加主键: Alter table tabname add primary key(col) /2\%X`]<
说明:删除主键: Alter table tabname drop primary key(col) g~AOKHUP
8、说明:创建索引:create [unique] index idxname on tabname(col....) 6W abw:
删除索引:drop index idxname 4z##4^9g
注:索引是不可更改的,想更改必须删除重新建。 /kY|PY
9、说明:创建视图:create view viewname as select statement @^';[P!
删除视图:drop view viewname c#6g[TE@
10、说明:几个简单的基本的sql语句 *1[v08?!
选择:select * from table1 where 范围
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插入:insert into table1(field1,field2) values(value1,value2) '!6Py1i
删除:delete from table1 where 范围 :W\xZ
更新:update table1 set field1=value1 where 范围 +#c3Y;JP
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! *Tt*\ O
排序:select * from table1 order by field1,field2 [desc] u< ,c
总数:select count as totalcount from table1 Q/,jv5
求和:select sum(field1) as sumvalue from table1 79 svlq=
平均:select avg(field1) as avgvalue from table1 W l+[{#
最大:select max(field1) as maxvalue from table1 uKcwVEu
最小:select min(field1) as minvalue from table1 #+-
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11、说明:几个高级查询运算词 dw
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A: UNION 运算符 7.o:(P1??g
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ?T(>!m
B: EXCEPT 运算符 z$>_c"D
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。
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C: INTERSECT 运算符 PmGW\E[ni
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。 z|V5/"
注:使用运算词的几个查询结果行必须是一致的。 !P &F6ViO=
12、说明:使用外连接 U Ux]
A、left outer join: . .|>|X4
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。 2y&m8_s-p
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 ?1?zmaS
B:right outer join: 0DBA 'Cv
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。 Eo$7W5hJ
C:full outer join: WmRx_d_
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。 x}W,B,q
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二、提升 lKd+,<
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) \P;%fN
法一:select * into b from a where 1<>1 aF9p%HPDw
法二:select top 0 * into b from a %U&O
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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) {/C
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insert into b(a, b, c) select d,e,f from b; LH4!QDK-
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) -o8H_MR
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ?Sq?f?
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. HD(4Ms
4、说明:子查询(表名1:a 表名2:b) 3K/32Wi
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) cGhnI&
5、说明:显示文章、提交人和最后回复时间 ,{HxX0
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b @,<@y>m7
6、说明:外连接查询(表名1:a 表名2:b) _JZwd9K
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c W -Yv0n3
7、说明:在线视图查询(表名1:a ) cViEvS r
select * from (SELECT a,b,c FROM a) T where t.a > 1; Vs-])Q?7J
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 3Ms`
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select * from table1 where time between time1 and time2 +ou
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select a,b,c, from table1 where a not between 数值1 and 数值2 s:y~vd(Vi
9、说明:in 的使用方法 KVVo_9S'
select * from table1 where a [not] in ('值1','值2','值4','值6') (3DjFT3
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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 "eq{_4dL
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) :@:i*2=
11、说明:四表联查问题: ,m-z D
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 ..... E|t.
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12、说明:日程安排提前五分钟提醒 ze<Lc/ ;X~
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 K85;7R5
13、说明:一条sql 语句搞定数据库分页 ccc*"_45#
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 }7>r,
14、说明:前10条记录 fb7Gy
select top 10 * form table1 where 范围 0UEEvD5
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.) 2F0@M|'
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) W0X/&v,k*
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 qn VxP&
(select a from tableA ) except (select a from tableB) except (select a from tableC) 7cGc`7
17、说明:随机取出10条数据 4aAuE0
select top 10 * from tablename order by newid() d`he
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18、说明:随机选择记录 2NHkK_B1P
select newid() M^c`j#NQ
19、说明:删除重复记录 o5 UM)g
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) +>#SB"'
20、说明:列出数据库里所有的表名 v=A]#O%
select name from sysobjects where type='U' zI5#'<n
21、说明:列出表里的所有的 Zl69d4vG
select name from syscolumns where id=object_id('TableName') M]O
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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。 "K3"s Ec%
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 @l)HX'z0d
显示结果: "+oP((9
type vender pcs L*xu<(>K
电脑 A 1 b'9\j.By
电脑 A 1 ^ lrq`1k
光盘 B 2 (!72Eaw:]
光盘 A 2 zo,`Vibx<
手机 B 3 WoVPp*zlX
手机 C 3 ,f@$a3}'Lx
23、说明:初始化表table1 "HCJ!
TRUNCATE TABLE table1 @6eM{3E.
24、说明:选择从10到15的记录 nRYHp7`
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc -}u=tiNG
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三、技巧 sN`2"t/s
1、1=1,1=2的使用,在SQL语句组合时用的较多 ke'aSD
"where 1=1" 是表示选择全部 "where 1=2"全部不选, |JZ3aS
如: v~f_~v5J!
if @strWhere !='' aDrF"j
begin s}8(__|
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere W(h].'N
end k[9~Er+
else u@j]U|FpY
begin )HHG3cvU
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ;D}8acQ
end {MP8B'r-6
我们可以直接写成 lSGtbSyDI
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ^}JGWGib=+
2、收缩数据库 "gD]K=
--重建索引 xq`mo
DBCC REINDEX OF [y$<jM
DBCC INDEXDEFRAG Sz_bjh yT}
--收缩数据和日志 )Gf"#TM[
DBCC SHRINKDB ch|4"&g
DBCC SHRINKFILE :ud<"I]:
3、压缩数据库 T bMW?Su
dbcc shrinkdatabase(dbname) N03)G2
4、转移数据库给新用户以已存在用户权限 Y?ADM(j
exec sp_change_users_login 'update_one','newname','oldname' G(g`>' m
go |m x)W}
5、检查备份集 5*M3sN
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' >?-etl
6、修复数据库
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ALTER DATABASE [dvbbs] SET SINGLE_USER <gvuCydsh
GO `w&Y[8+E
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK n}KF)W=
GO &I8Q'
ALTER DATABASE [dvbbs] SET MULTI_USER q"Ct=d
GO nitKX.t8
7、日志清除 !*[Fw1-J
SET NOCOUNT ON
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DECLARE @LogicalFileName sysname, %N jRD|
@MaxMinutes INT, (OA-Mgyc
@NewSize INT xF:}a:c@H
USE tablename -- 要操作的数据库名 =ttvC"4?
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 1r!o,0!d-'
@MaxMinutes = 10, -- Limit on time allowed to wrap log. M]FA
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@NewSize = 1 -- 你想设定的日志文件的大小(M) C[E[|s*l
-- Setup / initialize 6j*L]Sc
DECLARE @OriginalSize int 8>U{>]WG
SELECT @OriginalSize = size g+g0iS
FROM sysfiles D8Ntzsr6
WHERE name = @LogicalFileName ZGILV
SELECT 'Original Size of ' + db_name() + ' LOG is ' + /INjP~C
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + S511}KPbm/
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' K]~! =j)v
FROM sysfiles WJ%4IaT
WHERE name = @LogicalFileName ]]sy+$@~
CREATE TABLE DummyTrans y
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(DummyColumn char (8000) not null) M)m(
DECLARE @Counter INT, ;iol 2
@StartTime DATETIME, .<#oLM^
@TruncLog VARCHAR(255) yf >
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SELECT @StartTime = GETDATE(), #6fQ$x(F#j
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' $&fP%p
DBCC SHRINKFILE (@LogicalFileName, @NewSize) g 0Rny
EXEC (@TruncLog) ua!i3]18
-- Wrap the log if necessary. !p:kEIZ)y
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired *d~).z)
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ((& y:{?G
AND (@OriginalSize * 8 /1024) > @NewSize HuVx^y`
@
BEGIN -- Outer loop. p$5uS=:4`8
SELECT @Counter = 0 kn$2_I9
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) .|$:%"O&X
BEGIN -- update Ox | ?
INSERT DummyTrans VALUES ('Fill Log') O4)'78ATp
DELETE DummyTrans eo#2n8I>=1
SELECT @Counter = @Counter + 1 j{8;5 ?x
END !?AgAsSmc
EXEC (@TruncLog) U?@ s`.
END FfeX;pi
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 4q9+a7@
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Yz%A Kp
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' c0I;8z`b
FROM sysfiles &ikPa ,A
WHERE name = @LogicalFileName e8Ul^]
DROP TABLE DummyTrans B//2R)HS
SET NOCOUNT OFF 0|Rt[qwKb@
8、说明:更改某个表 [8kufMY|
exec sp_changeobjectowner 'tablename','dbo' 'P AIh*qA
9、存储更改全部表 VVd9VGvh
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch [6ycs[{!
@OldOwner as NVARCHAR(128), OON]E3yy
@NewOwner as NVARCHAR(128) "b~-`ni
AS Gy]ZYo(
DECLARE @Name as NVARCHAR(128) 6dH> 0l
DECLARE @Owner as NVARCHAR(128) (+(YQ2
DECLARE @OwnerName as NVARCHAR(128) J!\Cs1!f
DECLARE curObject CURSOR FOR g-C)y
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select 'Name' = name, f9%M:cl
'Owner' = user_name(uid) ;h f{B7
from sysobjects !7rk>YrY
where user_name(uid)=@OldOwner #F|q->2`o
order by name 0uZL*4A+C
OPEN curObject 8I>'xf
FETCH NEXT FROM curObject INTO @Name, @Owner +hIC N,8!
WHILE(@@FETCH_STATUS=0) eNHSfq
BEGIN U%:K11Kr
if @Owner=@OldOwner
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begin {)CN.z:O
set @OwnerName = @OldOwner + '.' + rtrim(@Name) [=EmDP:@
exec sp_changeobjectowner @OwnerName, @NewOwner /h]#}y j
end No\3kRB4bi
-- select @name,@NewOwner,@OldOwner qUSy0SQ/l
FETCH NEXT FROM curObject INTO @Name, @Owner 4MFdhJoN
END IPVD^a?
close curObject > w-fsL
deallocate curObject 'DhH:PR
GO 'K!u}py
10、SQL SERVER中直接循环写入数据 kndN} Vq
declare @i int >D\jyd$wh&
set @i=1 j7XUFA
while @i<30 Il4R R
begin @cS(Bb!(M
insert into test (userid) values(@i) >;sz(F3)
set @i=@i+1 dED&-e#
end vY"i^a`f
小记存储过程中经常用到的本周,本月,本年函数 t}Q
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Dateadd(wk,datediff(wk,0,getdate()),-1) X/8TRiTFv
Dateadd(wk,datediff(wk,0,getdate()),6) 2Wx~+@1y
Dateadd(mm,datediff(mm,0,getdate()),0) =Hd+KvA
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) K,f"Q<sU%
Dateadd(yy,datediff(yy,0,getdate()),0) JS!`eO/8
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) -"CXBKHb
上面的SQL代码只是一个时间段 E,}(jAq7
Dateadd(wk,datediff(wk,0,getdate()),-1) %a=^T?8
Dateadd(wk,datediff(wk,0,getdate()),6) nOm-Yb+F
就是表示本周时间段. V[#$Sz[G
下面的SQL的条件部分,就是查询时间段在本周范围内的: b(HbwOt~3
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) K ; eR)
而在存储过程中 (i.7\$4
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) /5wIbmz@I
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) )azK&f@tR|