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。 HZm
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一、基础
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1、说明:创建数据库 HFr3(gNj@
CREATE DATABASE database-name *I67SBt
2、说明:删除数据库 W~tOH=9>
drop database dbname p[)<d_
3、说明:备份sql server ]'Yw#YB
--- 创建 备份数据的 device mig3.is
USE master W,~1KUTc
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' DS C4
--- 开始 备份 `/zt&=`VB
BACKUP DATABASE pubs TO testBack Dkb&/k:)
4、说明:创建新表 4I*Mc%dD
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ;N\?]{ L
根据已有的表创建新表: X2[cR;;'
A:create table tab_new like tab_old (使用旧表创建新表) C6w{"[Wv=X
B:create table tab_new as select col1,col2... from tab_old definition only [S:)UvB
5、说明:删除新表 ? st#6=M
drop table tabname ak>NKK8P
6、说明:增加一个列 ~N9-an
Alter table tabname add column col type bY~ v0kg
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。 "o3"1s>d{
7、说明:添加主键: Alter table tabname add primary key(col) )0mDN.
说明:删除主键: Alter table tabname drop primary key(col) }^[@m#
8、说明:创建索引:create [unique] index idxname on tabname(col....) \2pFFVT
删除索引:drop index idxname 2[po~}2-0
注:索引是不可更改的,想更改必须删除重新建。 V+24- QWh
9、说明:创建视图:create view viewname as select statement 9C;Y5E~'L
删除视图:drop view viewname 3(+#^aw
10、说明:几个简单的基本的sql语句 c0&'rxi(B
选择:select * from table1 where 范围 05B+WJ1
插入:insert into table1(field1,field2) values(value1,value2) YZRB4T9
删除:delete from table1 where 范围 5$U>M
更新:update table1 set field1=value1 where 范围 kW&Z%k
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! # &83;uys
排序:select * from table1 order by field1,field2 [desc] .,Qnn}:l
总数:select count as totalcount from table1 ~ fEs!hl
求和:select sum(field1) as sumvalue from table1 sRQh~5kM
平均:select avg(field1) as avgvalue from table1 AnY)T8w
最大:select max(field1) as maxvalue from table1 /zf>>O`
最小:select min(field1) as minvalue from table1 }G+A_HF ^
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11、说明:几个高级查询运算词 /\cu!yiX
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A: UNION 运算符 VtiqAh}4
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 xsDa!
B: EXCEPT 运算符 jHlOP,kc
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 I<./(X[H:#
C: INTERSECT 运算符 }.UI&UZ-
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 R.IUBw5;/
注:使用运算词的几个查询结果行必须是一致的。 m}[~A@qD
12、说明:使用外连接 Q\#{2!I
A、left outer join: QYfAf3te
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 c48J!,jCd'
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c #oJbrh9J6
B:right outer join: /~l/_Jct@G
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 (1AA;)`Kp
C:full outer join: x56
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全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 YD46Z~$
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二、提升 G:c8`*5Q
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) NnLhJPh
法一:select * into b from a where 1<>1 ~26s7S}
法二:select top 0 * into b from a #EmffVtY
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Uty(sDtu
insert into b(a, b, c) select d,e,f from b; Q;XHHk
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) $;2eH
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 \gp,Txueb
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 7t-*L}~WA
4、说明:子查询(表名1:a 表名2:b) foz5D9sQ
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) hGA!1a4 c
5、说明:显示文章、提交人和最后回复时间 Naf`hE9
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b "T{~,'T
6、说明:外连接查询(表名1:a 表名2:b) d@6:|auO
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 827)n[#%|
7、说明:在线视图查询(表名1:a ) 9U7Mu;4
select * from (SELECT a,b,c FROM a) T where t.a > 1; 1( ?CNW[
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 t}XB|h
select * from table1 where time between time1 and time2 X(!AI|6Bt
select a,b,c, from table1 where a not between 数值1 and 数值2 >2lAy:B5
9、说明:in 的使用方法 F8S~wW=\w
select * from table1 where a [not] in ('值1','值2','值4','值6') u3M`'YCb
10、说明:两张关联表,删除主表中已经在副表中没有的信息 l|vWeBs
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) +f\pk \Ith
11、说明:四表联查问题: :!I)r$
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 ..... D]pK=247
12、说明:日程安排提前五分钟提醒 g<2lPH
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 //X e*0
13、说明:一条sql 语句搞定数据库分页 9B+ zJ Vte
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 m0I #
14、说明:前10条记录 /OhaERv
select top 10 * form table1 where 范围 MdVCD^B
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.) f/0v'
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Ez/\bE
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 A]Q1&qM%
(select a from tableA ) except (select a from tableB) except (select a from tableC) \3Q:K|
17、说明:随机取出10条数据 KH2F#[
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select top 10 * from tablename order by newid() vZ[$H
18、说明:随机选择记录 ^A *]&%(h
select newid() ZL-uwI!`D
19、说明:删除重复记录 2fkIdy#n@
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) nr<WO~Xw~
20、说明:列出数据库里所有的表名 QJM-`(
select name from sysobjects where type='U' NJ|NJp&0
21、说明:列出表里的所有的 |D;_:x9
select name from syscolumns where id=object_id('TableName') O+G~Qp0b>
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 gdoJ4b
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type QL)>/%yU
显示结果: <a8#0ojm
type vender pcs [2GXAvXsT
电脑 A 1 Sni&?tcY
电脑 A 1 CRZi;7`*1
光盘 B 2 oupJJDpP
光盘 A 2 uY&=eQ_Cb
手机 B 3 <@u0.-]
手机 C 3 //\ds71h
23、说明:初始化表table1 `fQM
TRUNCATE TABLE table1 'R^iKNPs
24、说明:选择从10到15的记录 KqN!?anPr
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc uz*d^gr}
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三、技巧 u$WBc\j
1、1=1,1=2的使用,在SQL语句组合时用的较多 -1Djo:y
"where 1=1" 是表示选择全部 "where 1=2"全部不选, $z= 0[%L
如: X3P&"}a
if @strWhere !='' %
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begin Q/9a,85
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere %lXbCE:[
end fph-v -cl
else FQ+8J 7
begin pU
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' jMK3T
end vGXWwQ.1Tp
我们可以直接写成 /wr6\53J
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere pPoH5CzcK
2、收缩数据库 {J{1`@
--重建索引 ;!'qtw"CB
DBCC REINDEX :FnOS<_B
DBCC INDEXDEFRAG LFCTr/,
--收缩数据和日志 $np=eT)
DBCC SHRINKDB T}UT7W|
DBCC SHRINKFILE .FuA;:@%\
3、压缩数据库 a lrt*V|=
dbcc shrinkdatabase(dbname) #-,g&)`]
4、转移数据库给新用户以已存在用户权限 \0D$Mie
exec sp_change_users_login 'update_one','newname','oldname' /^J2B8y
go f:xUPH?+
5、检查备份集 [1NaH
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' L*P_vCC
6、修复数据库 [d}qG#N
ALTER DATABASE [dvbbs] SET SINGLE_USER 6A}eSG3
GO !&W|myN^
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Hfke
GO |Z
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ALTER DATABASE [dvbbs] SET MULTI_USER Lj4&_b9
GO u2 7S%2P
7、日志清除 o"RJ.w:dn
SET NOCOUNT ON -)X{n?i
DECLARE @LogicalFileName sysname, ^b=XV&{q
@MaxMinutes INT, zyDZ$Dhka
@NewSize INT N?$7Z v[G
USE tablename -- 要操作的数据库名 c)03Ms4
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 }?J~P%HpF
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 4Hk6b09
@NewSize = 1 -- 你想设定的日志文件的大小(M) >&1um5K
-- Setup / initialize $Buf#8)F*
DECLARE @OriginalSize int 2% %|fU9
SELECT @OriginalSize = size ~6kJ~R4
FROM sysfiles YwXXXh
WHERE name = @LogicalFileName PRwu
SELECT 'Original Size of ' + db_name() + ' LOG is ' + \dTQQ
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 9k}<F z"^.
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' izf~w^/
FROM sysfiles 9^!wUwB
WHERE name = @LogicalFileName 7WP%J-
CREATE TABLE DummyTrans H*rx{ F?
(DummyColumn char (8000) not null) b_l3+'#ofM
DECLARE @Counter INT, jN6b*-2
@StartTime DATETIME, 4>YU8/Rw
@TruncLog VARCHAR(255) ]^ #`j
SELECT @StartTime = GETDATE(), )v1CC..
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' s^cc@C
DBCC SHRINKFILE (@LogicalFileName, @NewSize) .H2qs{N!
EXEC (@TruncLog) w" JGO
-- Wrap the log if necessary. Gqt-_gga
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired O3Uh+gKQ
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) +]c}rWm
AND (@OriginalSize * 8 /1024) > @NewSize bDWeU}
BEGIN -- Outer loop. U(~U!O}
SELECT @Counter = 0 4V$fGjJ3
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) jTfi@5aPY
BEGIN -- update o%`npi1y
INSERT DummyTrans VALUES ('Fill Log') ik5|,#}m&
DELETE DummyTrans q^*6C[G B
SELECT @Counter = @Counter + 1 E/mw* c^
END x@m<Ym-
EXEC (@TruncLog) j{;|g%5t
END KDD@%E
SELECT 'Final Size of ' + db_name() + ' LOG is ' + @rwU 1T33
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ue6d~8&
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' M6Pw/S!
FROM sysfiles ] H&c'
WHERE name = @LogicalFileName [@3SfQ
DROP TABLE DummyTrans "OL~ul5
SET NOCOUNT OFF }lP 5GT2
8、说明:更改某个表 /C$
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exec sp_changeobjectowner 'tablename','dbo' eh<rRx"[
9、存储更改全部表 ]*;F. pZ
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch .oR3Q/|k]
@OldOwner as NVARCHAR(128), [N:BM% FQ
@NewOwner as NVARCHAR(128) (ua q<Cvg
AS rl?7W];
DECLARE @Name as NVARCHAR(128) a4&:@`=
DECLARE @Owner as NVARCHAR(128) nm @']
DECLARE @OwnerName as NVARCHAR(128)
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DECLARE curObject CURSOR FOR {155b0
select 'Name' = name, n+;vjVS%
'Owner' = user_name(uid) P+Z\3re
from sysobjects "-
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where user_name(uid)=@OldOwner \A<v=VM|
order by name -eml
OPEN curObject g19S
FETCH NEXT FROM curObject INTO @Name, @Owner Au5rR>W
WHILE(@@FETCH_STATUS=0) 2\0Oji\6
BEGIN a2yE:16o6
if @Owner=@OldOwner eN/G i<
begin wqy^8N[K]
set @OwnerName = @OldOwner + '.' + rtrim(@Name) xU}M;4kH~
exec sp_changeobjectowner @OwnerName, @NewOwner O>V(cmqE`
end -@M3Dwsi3
-- select @name,@NewOwner,@OldOwner Rri`dmH
FETCH NEXT FROM curObject INTO @Name, @Owner 6Cc7ejt|u
END 7>n"}8i
close curObject fg&eoI'f
deallocate curObject \.<KA
GO >]&X ^V%Q#
10、SQL SERVER中直接循环写入数据 EGS%C%>l/o
declare @i int = .`jjDJ
set @i=1 Ld(NhB'7
while @i<30 t1ze-Ht;
begin T?npQA07=
insert into test (userid) values(@i) "8(U\KaX
set @i=@i+1 eH
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end ai;\@$ cq
小记存储过程中经常用到的本周,本月,本年函数 6>DLp}d
Dateadd(wk,datediff(wk,0,getdate()),-1) 64U6C *w+
Dateadd(wk,datediff(wk,0,getdate()),6) f=aIXhiYU
Dateadd(mm,datediff(mm,0,getdate()),0) 8_xLl2
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 8h.V4/?
Dateadd(yy,datediff(yy,0,getdate()),0) 3t(c_:[%
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) M{Gxjmdx
上面的SQL代码只是一个时间段 6D/ '`
Dateadd(wk,datediff(wk,0,getdate()),-1) SDBt @=Nl
Dateadd(wk,datediff(wk,0,getdate()),6) B QjGv?p0s
就是表示本周时间段. KcXpH]>!9
下面的SQL的条件部分,就是查询时间段在本周范围内的: 6RK\}@^=K
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) "!Lkp2\
而在存储过程中 'UfeluMd
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) E5UcZ7
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ?)i1b\4Go