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。 W!jg
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一、基础 6> DmcG:.
1、说明:创建数据库 2UbTKN
CREATE DATABASE database-name M1HGXdN* B
2、说明:删除数据库 #EG$HX]
drop database dbname wa1Qt
3、说明:备份sql server y\?NB:=%
--- 创建 备份数据的 device z*,J0)<Q
USE master A r,fmq
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 'LX]/D
--- 开始 备份 |&u4Q /0
BACKUP DATABASE pubs TO testBack dQljG.PiK
4、说明:创建新表 BS*Y3 $
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) XU5GmGu_+
根据已有的表创建新表: AJYZ`
A:create table tab_new like tab_old (使用旧表创建新表) }t%2giJ
B:create table tab_new as select col1,col2... from tab_old definition only pE4yx5r5
5、说明:删除新表 h[(.
drop table tabname .QVN&UyZ
6、说明:增加一个列 9 `+RmX;m
Alter table tabname add column col type T;C0t9Yew
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。 'f_[(o+n
7、说明:添加主键: Alter table tabname add primary key(col) 8{4SaT.-Rm
说明:删除主键: Alter table tabname drop primary key(col) }kZ)|/]kn
8、说明:创建索引:create [unique] index idxname on tabname(col....) 3Z_\.Z1R@
删除索引:drop index idxname -^ceTzW+
注:索引是不可更改的,想更改必须删除重新建。 +?9.
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9、说明:创建视图:create view viewname as select statement 7MZ(tOR
删除视图:drop view viewname 328gTP1
10、说明:几个简单的基本的sql语句 CpLLsp hy
选择:select * from table1 where 范围 ;Z 6ngS
插入:insert into table1(field1,field2) values(value1,value2) B>r>z5
删除:delete from table1 where 范围 sD=iHO
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更新:update table1 set field1=value1 where 范围 [cso$Tv
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 6^vz+oN
排序:select * from table1 order by field1,field2 [desc] ~{cG"
总数:select count as totalcount from table1 b=PB" -
求和:select sum(field1) as sumvalue from table1 1ir~WFP
平均:select avg(field1) as avgvalue from table1 p N+1/m,
最大:select max(field1) as maxvalue from table1 B%(-UTQf
最小:select min(field1) as minvalue from table1 | K w}S/F
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11、说明:几个高级查询运算词 ab8F\%y-8
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A: UNION 运算符 #-7w|
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。 UPcx xtC
B: EXCEPT 运算符 8~|tl,
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。 'U*Kb
C: INTERSECT 运算符 Y]neTX [ef
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。 AGMrBd|J{
注:使用运算词的几个查询结果行必须是一致的。 jM[]Uh
12、说明:使用外连接 hQ _gOI
A、left outer join: _FxQl]@
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。 yL#2|t(
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 qr'P0+|~5
B:right outer join: v=J[p;H^H
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。 eh /QFm
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C:full outer join: >5M Hn@
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。 Oi4y~C_Xd
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二、提升 -F&*>?I
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) !Ct'H1J-
法一:select * into b from a where 1<>1 94'0X
法二:select top 0 * into b from a D:#e;K
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) s)5W:`MH?
insert into b(a, b, c) select d,e,f from b; uePa4e!
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) C^fUhLVSZ^
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ;%mYsQ
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. L4!T
4、说明:子查询(表名1:a 表名2:b) \9%RY]TK3
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) ICm/9Onh&
5、说明:显示文章、提交人和最后回复时间 4h$W4NJK
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b JXAH/N&i
6、说明:外连接查询(表名1:a 表名2:b) ((
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c XAb-K?)
7、说明:在线视图查询(表名1:a ) \[Q* d
select * from (SELECT a,b,c FROM a) T where t.a > 1; /2Qgg`^)
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 Zp_vv@s
select * from table1 where time between time1 and time2 EL:Az~]V
select a,b,c, from table1 where a not between 数值1 and 数值2 q-D|96>8
9、说明:in 的使用方法 vN$j@h .
select * from table1 where a [not] in ('值1','值2','值4','值6') rssn'h
10、说明:两张关联表,删除主表中已经在副表中没有的信息 us >$f20T
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) gaVQ3NqF
11、说明:四表联查问题: cUD}SOW
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 ..... A5kz(pj
12、说明:日程安排提前五分钟提醒 'D[g{LkL
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 !A=>B=.|D
13、说明:一条sql 语句搞定数据库分页 Y N*"q'Yz_
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 H q."_i{I
14、说明:前10条记录 -iySU 6
select top 10 * form table1 where 范围 &k@r23V7r
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.) |yYu!+U
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 2>h.K/pC
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 lQl
(select a from tableA ) except (select a from tableB) except (select a from tableC) :M9 E
17、说明:随机取出10条数据 8jjq)d4#
select top 10 * from tablename order by newid() woyeKOr
18、说明:随机选择记录 Hmv@7$9s\
select newid() ~]C m
19、说明:删除重复记录 <}t<A
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) H-'~c\)
20、说明:列出数据库里所有的表名 @ZtDjxN
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select name from sysobjects where type='U' _su$]s
21、说明:列出表里的所有的 ]`u_d}`
select name from syscolumns where id=object_id('TableName') #9u2LK
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。 m8NKuhu
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 :uQ~?amM
显示结果: MtXTh*4
type vender pcs +@jX|
电脑 A 1 sY@x(qkIOc
电脑 A 1 ![hVTZ,hyZ
光盘 B 2 ;6/dFOZn
光盘 A 2 HWxwG'EEY,
手机 B 3 \Ss6F]K]
手机 C 3 IrTMZG
23、说明:初始化表table1 f) @-X!
TRUNCATE TABLE table1 ?0hEd9TU
24、说明:选择从10到15的记录 9MR,3/&N
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Mhiz{Td
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三、技巧 h?+bW'm
1、1=1,1=2的使用,在SQL语句组合时用的较多 25m!Bf
"where 1=1" 是表示选择全部 "where 1=2"全部不选, EjFK zx
如: Bv(c`JE~;
if @strWhere !='' >Qold7
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begin Ln@n6*%(/
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere &M2SqeR62;
end :vRUb>z
else mIm.+U`a2
begin ).uR@j
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ZhYOz
end i2Cw#x0s
我们可以直接写成 ;.|).y1/`
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Gk2R:\/Y
2、收缩数据库 _NkbB"+L
--重建索引 \A=:6R%Qb
DBCC REINDEX '
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DBCC INDEXDEFRAG #25%17
--收缩数据和日志 $G.ws
DBCC SHRINKDB 9Netnzv%
DBCC SHRINKFILE 2}8xY:|@(U
3、压缩数据库 3+d_5l;m)
dbcc shrinkdatabase(dbname) PA<<{\dp
4、转移数据库给新用户以已存在用户权限 zpM%L:S
exec sp_change_users_login 'update_one','newname','oldname' MO-)j_o-Z
go t182&gpd`
5、检查备份集 C3z#A3&J
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' <j^bk"l p
6、修复数据库 w;4FN'
ALTER DATABASE [dvbbs] SET SINGLE_USER \'.#of
GO NZ=`iA8)X
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 8nQjD<-
GO 0VBbSn}Z<
ALTER DATABASE [dvbbs] SET MULTI_USER jce^Xf
GO ,+hH|$
7、日志清除 K3On8
SET NOCOUNT ON "*N=aHsj
DECLARE @LogicalFileName sysname, Y1Sfhs)
@MaxMinutes INT, uIb,n5
@NewSize INT M qG`P
USE tablename -- 要操作的数据库名 c037#&Q%#
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Ql.abU
@MaxMinutes = 10, -- Limit on time allowed to wrap log. i_kKE+Q
@NewSize = 1 -- 你想设定的日志文件的大小(M) 76j5
-- Setup / initialize FatLc|[
DECLARE @OriginalSize int +`s%-}-r
SELECT @OriginalSize = size QGM@m:O
FROM sysfiles 5\\a49k.p
WHERE name = @LogicalFileName R1lC_G]
SELECT 'Original Size of ' + db_name() + ' LOG is ' + mH\eJ
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + "JJEF2e@Z
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' @EV*QC2l;Y
FROM sysfiles QM'Db`B
WHERE name = @LogicalFileName E0-<-w3'
CREATE TABLE DummyTrans :$gR
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(DummyColumn char (8000) not null) f%JC;Y
DECLARE @Counter INT, K6X}d,g
@StartTime DATETIME, w] =q>p
@TruncLog VARCHAR(255) s+l3]Hd
SELECT @StartTime = GETDATE(), %9lx)w
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' F|3iKK022
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 6x 8P}?
EXEC (@TruncLog) ~L7@,d :
-- Wrap the log if necessary. **!
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Gn7P` t*.
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) mpysnKH
AND (@OriginalSize * 8 /1024) > @NewSize =
gbB)u-Pc
BEGIN -- Outer loop. xQK;3b
SELECT @Counter = 0 @Wb_Sz4`
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 2qkZ B0[
BEGIN -- update o2vBY]Tj
INSERT DummyTrans VALUES ('Fill Log') Fy8$'oc
DELETE DummyTrans #FQkwX'g
SELECT @Counter = @Counter + 1 _0: }"!Gq
END S#wy+*
EXEC (@TruncLog) /
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END M)v4>Rw+
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ;LjTsF'
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + eK=<a<tx
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' vl67Xtk4
FROM sysfiles "-HmXw1+t
WHERE name = @LogicalFileName (;.wsz&K
DROP TABLE DummyTrans CW9vC
SET NOCOUNT OFF D8S3YdJ
8、说明:更改某个表 p3R: 3E6p
exec sp_changeobjectowner 'tablename','dbo' nnol)|C{5Y
9、存储更改全部表 dqu+-43I|
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch *c1)x
@OldOwner as NVARCHAR(128), isiehKkD
@NewOwner as NVARCHAR(128) q+}KAk|]V
AS TC$)::C1
DECLARE @Name as NVARCHAR(128) U1!#TD)@
DECLARE @Owner as NVARCHAR(128) 0`D`
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DECLARE @OwnerName as NVARCHAR(128) ]#*S. r]
DECLARE curObject CURSOR FOR q*E<~!jL
select 'Name' = name, G!L(K
'Owner' = user_name(uid) N(W;\>P
from sysobjects HZDeQx`*s
where user_name(uid)=@OldOwner ]dj
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order by name jF r[T
OPEN curObject ~aZy52H_#.
FETCH NEXT FROM curObject INTO @Name, @Owner 2uln)]
WHILE(@@FETCH_STATUS=0) VsJ4sb7
BEGIN |2t1m 6\j
if @Owner=@OldOwner >&g^ `
begin , A@uSfC(
set @OwnerName = @OldOwner + '.' + rtrim(@Name) V@C8HTg
exec sp_changeobjectowner @OwnerName, @NewOwner #FNSE*Y
end v%2 @M
-- select @name,@NewOwner,@OldOwner >nqCUhS
FETCH NEXT FROM curObject INTO @Name, @Owner :kb2v1{\
END f}%paE"
close curObject 7kDqgod^A
deallocate curObject KyQd6 1
GO rTmVHt
10、SQL SERVER中直接循环写入数据 d(X/N2~g
declare @i int }8e_
set @i=1 E'ay
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while @i<30 ^S%xaA9
begin P]mJ01@'
insert into test (userid) values(@i) BGOajYD
set @i=@i+1 2.>aL
end Q dPqcw4+X
小记存储过程中经常用到的本周,本月,本年函数 yRyUOTK
Dateadd(wk,datediff(wk,0,getdate()),-1) qe3d,!
Dateadd(wk,datediff(wk,0,getdate()),6) bK69Rb@\A
Dateadd(mm,datediff(mm,0,getdate()),0) 4A{6)<e
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) q4y sTm
Dateadd(yy,datediff(yy,0,getdate()),0) 2P(6R.8;6
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) C4H$w:bVk
上面的SQL代码只是一个时间段 D<wz%*
Dateadd(wk,datediff(wk,0,getdate()),-1) FD[o94`%
Dateadd(wk,datediff(wk,0,getdate()),6) 3"O&IY<
就是表示本周时间段. L}M%z9K`h
下面的SQL的条件部分,就是查询时间段在本周范围内的: lh`ZEvt
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) nQaryL
而在存储过程中 ZR8%h<
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) xMr=tU1C
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) kE`Fg(M