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。 o{m$b2BW
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一、基础 oQFpIX;\m
1、说明:创建数据库 UP%X`
CREATE DATABASE database-name
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2、说明:删除数据库 ;w[|IRa
drop database dbname %;9wToyK>
3、说明:备份sql server P#"vlNa
--- 创建 备份数据的 device AgO:"'c
USE master ]`]m41+w
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' .,UpI|b
--- 开始 备份 Q{V|{yV^y
BACKUP DATABASE pubs TO testBack ?ZE1>L7e
4、说明:创建新表 `QAotSO+
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) WZ;f3
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根据已有的表创建新表: G)iV
A:create table tab_new like tab_old (使用旧表创建新表) [u=b[(
B:create table tab_new as select col1,col2... from tab_old definition only A1>R8Zuhy
5、说明:删除新表 _D[vMr[
drop table tabname Sh}AGNE'
6、说明:增加一个列 GS4!c8>
Alter table tabname add column col type @va)j
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 [uW{Ap ~2
7、说明:添加主键: Alter table tabname add primary key(col) D 0\
说明:删除主键: Alter table tabname drop primary key(col) 'C!b($Y
8、说明:创建索引:create [unique] index idxname on tabname(col....) , z<\ Z!+=
删除索引:drop index idxname Dm"GCV
注:索引是不可更改的,想更改必须删除重新建。 Skq%S`1%Q
9、说明:创建视图:create view viewname as select statement iVREkZ2SC
删除视图:drop view viewname rW&8#&
10、说明:几个简单的基本的sql语句 %)?$82=2
选择:select * from table1 where 范围 SP97Q-
插入:insert into table1(field1,field2) values(value1,value2) 0ppZ~}&
删除:delete from table1 where 范围 O. V!L
更新:update table1 set field1=value1 where 范围 l%rwJLN1
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! }| (KI
排序:select * from table1 order by field1,field2 [desc] %7z
总数:select count as totalcount from table1 $@7S+'Q3
求和:select sum(field1) as sumvalue from table1 Pv+[N{
平均:select avg(field1) as avgvalue from table1 VD<W
最大:select max(field1) as maxvalue from table1 *3s4JK
最小:select min(field1) as minvalue from table1 [x'xbQLGd
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11、说明:几个高级查询运算词 NUX0=(k
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A: UNION 运算符 .UU BAyjm
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 F]q pDv
B: EXCEPT 运算符 L/_OgL]YdI
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 =O<Ul~JRK
C: INTERSECT 运算符 F9^8/Z
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 % tN{
注:使用运算词的几个查询结果行必须是一致的。 a.y_o50#T
12、说明:使用外连接 a#nVRPU8m
A、left outer join: %S]H
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 Sdy\s5
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 2fu|X#R
B:right outer join: AVyqtztQ
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 weEmUw Z
C:full outer join: ,q] Wi#
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 ik=~`3Zp0
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二、提升 c8v+eyn
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) jV;&*4if
法一:select * into b from a where 1<>1 lUJ/ nG0l
法二:select top 0 * into b from a Hc ]/0:
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Eb7qM.Q] &
insert into b(a, b, c) select d,e,f from b; hw:zak#j,
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) ]j(2FM)#
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 `7zz&f9dDX
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. U
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4、说明:子查询(表名1:a 表名2:b) j{?,nJdQ
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) )2C_6eR
5、说明:显示文章、提交人和最后回复时间 UN>!#Ji:$
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 9[N+x2q
6、说明:外连接查询(表名1:a 表名2:b) "gADHt=MIR
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c [ Lt1OdGl
7、说明:在线视图查询(表名1:a ) g4cmYg3
select * from (SELECT a,b,c FROM a) T where t.a > 1; >wS52ng
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 *y9 iuJ}
select * from table1 where time between time1 and time2 oj /:
select a,b,c, from table1 where a not between 数值1 and 数值2 I2hX;pk,
9、说明:in 的使用方法 kz\
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select * from table1 where a [not] in ('值1','值2','值4','值6') X2hV)8Sk
10、说明:两张关联表,删除主表中已经在副表中没有的信息 e; 5n.+m
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ,R5NKWo
11、说明:四表联查问题: 9JV(}v5[
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 ..... IT5AB?bxH
12、说明:日程安排提前五分钟提醒 J?&lpsB3_l
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 PsU.dv[
13、说明:一条sql 语句搞定数据库分页 55)!cw4
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 E}sjl
14、说明:前10条记录 D$
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select top 10 * form table1 where 范围 9!zUv:;
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.) ^B8%Re%
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) O'{UAb+-
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 &2C6q04b
(select a from tableA ) except (select a from tableB) except (select a from tableC) B- =*"H?q
17、说明:随机取出10条数据 u1s^AW8 y
select top 10 * from tablename order by newid() 3YVG|Bc~_
18、说明:随机选择记录 4SIi<cS0
select newid() Nlemb:'eP3
19、说明:删除重复记录 _IBIx\F
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) v_?0|Ei[
20、说明:列出数据库里所有的表名 o6,$;-?F_
select name from sysobjects where type='U' Aq@_^mq1A
21、说明:列出表里的所有的 - ?_aYJ
select name from syscolumns where id=object_id('TableName') O3WhO@`6)
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 ES p)%
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type h$.y)v
显示结果: kKFmTo
type vender pcs *jM~VTXwt
电脑 A 1 vY0C(jK
电脑 A 1 zim]3%b*A;
光盘 B 2 g
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光盘 A 2 *@[DG)N
手机 B 3 L/dG0a@1X
手机 C 3 A@-nn]
23、说明:初始化表table1 OBaG'lrZy
TRUNCATE TABLE table1 (oO*|\9u
24、说明:选择从10到15的记录 <cm,U)j2
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Sd/?xyF1(
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三、技巧 b-R!oP+vP
1、1=1,1=2的使用,在SQL语句组合时用的较多 Hv2t_QjKT
"where 1=1" 是表示选择全部 "where 1=2"全部不选, OEmz`JJ67
如: 4UD<g+|
if @strWhere !='' 7WK^eW"y8
begin )\#w=P
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 9SF2
end -3`S;Dmn
else 'lNy&
begin Kcv7C{-/
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ep`WYR|B
end 6p`AdDV
我们可以直接写成 q8%T)$!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 1H sfCky{
2、收缩数据库 ^]:w5\DG
--重建索引 t=M:L[bis;
DBCC REINDEX m`luMt9
DBCC INDEXDEFRAG R!IODXP=
--收缩数据和日志 1%~yb Q
DBCC SHRINKDB P(pw$
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DBCC SHRINKFILE JW[y
3、压缩数据库 tUouO0_l
dbcc shrinkdatabase(dbname) .y'iF>QQ\
4、转移数据库给新用户以已存在用户权限 3\_ae2GW
exec sp_change_users_login 'update_one','newname','oldname' !]AM#LJ
go s%F}4W2s
5、检查备份集 0G`_dMN
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' mYLqT$t.+
6、修复数据库 KW.*LoO
ALTER DATABASE [dvbbs] SET SINGLE_USER \HX'^t`
GO q
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK y)iT-$bQ
GO j\l9|vpp
ALTER DATABASE [dvbbs] SET MULTI_USER .^6;_s>FN
GO cojtQD6
7、日志清除 u!I Es
SET NOCOUNT ON r}kQ<SRx
DECLARE @LogicalFileName sysname, k"_i7
@MaxMinutes INT, ):"Z7~j=
@NewSize INT I&JVY8'
USE tablename -- 要操作的数据库名 _Iz JxAcJ
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 p!qV!:
@MaxMinutes = 10, -- Limit on time allowed to wrap log. l&3f<e
@NewSize = 1 -- 你想设定的日志文件的大小(M) 2ghTAsUx9
-- Setup / initialize AX6z4G
DECLARE @OriginalSize int 533n
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SELECT @OriginalSize = size thG;~W
FROM sysfiles #OlU|I
WHERE name = @LogicalFileName irj{Or^k
SELECT 'Original Size of ' + db_name() + ' LOG is ' + fik*-$V`
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + =eG?O7z&
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' h'*>\eC6
FROM sysfiles 'Cw&9cL9w
WHERE name = @LogicalFileName %`*`HU#X
CREATE TABLE DummyTrans 0($@9k4!/
(DummyColumn char (8000) not null) &!/E&e$_
DECLARE @Counter INT, @J J,$?
@StartTime DATETIME, "^sh:{
@TruncLog VARCHAR(255) QwF\s13
SELECT @StartTime = GETDATE(), B~S"1EE[
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' mqw5\7s ?
DBCC SHRINKFILE (@LogicalFileName, @NewSize) u,h ,;'J
EXEC (@TruncLog) Bw5zh1ALC;
-- Wrap the log if necessary. $P<T`3Jg
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired :r5DR`Rfm
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) w-f[h
AND (@OriginalSize * 8 /1024) > @NewSize &T7|f!y
BEGIN -- Outer loop. <cC 0l-=
SELECT @Counter = 0 Fh2$,$
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 06hzCWm#
BEGIN -- update gz{~\0y
INSERT DummyTrans VALUES ('Fill Log') LOm*=MVex
DELETE DummyTrans i%~^3/K
SELECT @Counter = @Counter + 1 "9mVBa|Q
END .KzGb4U
EXEC (@TruncLog) +7yirp~`K
END 6yDc4AX
SELECT 'Final Size of ' + db_name() + ' LOG is ' + :exgdm;N
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + #&Xr2?E@
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' |jh&a+4W
FROM sysfiles +|Tz<\.C
WHERE name = @LogicalFileName -)cau-(X
DROP TABLE DummyTrans [V vTR#^
SET NOCOUNT OFF 9VqE:c /
8、说明:更改某个表 (~C_zG
exec sp_changeobjectowner 'tablename','dbo' ~ ^)D#Lo
9、存储更改全部表 a/})X[2
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 5U%J,W
@OldOwner as NVARCHAR(128), @|e4.(9A
@NewOwner as NVARCHAR(128) }>)e~\Tdzb
AS BQ X6Q<
DECLARE @Name as NVARCHAR(128) /(/Z~J[
DECLARE @Owner as NVARCHAR(128) 4!%@{H`3
DECLARE @OwnerName as NVARCHAR(128) g43j-[j)
DECLARE curObject CURSOR FOR 5AX
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select 'Name' = name, nC-=CMWWr
'Owner' = user_name(uid) _(#HQd,i
from sysobjects $P=B66t
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where user_name(uid)=@OldOwner ll]MBq
order by name 4CUoXs'
OPEN curObject wR7Ja
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FETCH NEXT FROM curObject INTO @Name, @Owner TH;kJ{[}
WHILE(@@FETCH_STATUS=0) R`IFKmA EJ
BEGIN '7lHWqN<
if @Owner=@OldOwner VnZRsFY<^
begin 2#<)-Cak
set @OwnerName = @OldOwner + '.' + rtrim(@Name) E_fH,YJ?9
exec sp_changeobjectowner @OwnerName, @NewOwner *wH.]$
end VR8 kY&
-- select @name,@NewOwner,@OldOwner s}
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FETCH NEXT FROM curObject INTO @Name, @Owner xj6@85^
END i~};5j(
close curObject fGeDygV^`
deallocate curObject SG5GJCkc
GO fX
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10、SQL SERVER中直接循环写入数据 1Q5:Vo^B#
declare @i int (D.B'V#>
set @i=1 Yk;-]qi7
while @i<30 Aof)WKo
begin a Uy!(Y
insert into test (userid) values(@i) &:>3tFQSH
set @i=@i+1 #[
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end lx'^vK% F
小记存储过程中经常用到的本周,本月,本年函数 Po)!vL"
Dateadd(wk,datediff(wk,0,getdate()),-1) e9LP!"@EY
Dateadd(wk,datediff(wk,0,getdate()),6) ab}Kt($
Dateadd(mm,datediff(mm,0,getdate()),0) Io(*_3V)B
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) kFRl+,bi~
Dateadd(yy,datediff(yy,0,getdate()),0) KT4h3D`,
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) +jEtu[ ;
上面的SQL代码只是一个时间段 NsPAWI|4
Dateadd(wk,datediff(wk,0,getdate()),-1) f:\)oIW9Kk
Dateadd(wk,datediff(wk,0,getdate()),6) <:n!qQS6
就是表示本周时间段. N4[`pXM6
下面的SQL的条件部分,就是查询时间段在本周范围内的: & t.G4
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) [%uj+?}6O
而在存储过程中 Qm"&=<
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) u~C,x3yr
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 8opd0'SNaB