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。 o6R(BMwGa
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一、基础 ,3j*D+
1、说明:创建数据库 THJ+OnP
CREATE DATABASE database-name _xUXt)k
2、说明:删除数据库 U PC& O
drop database dbname K&*FI (a
3、说明:备份sql server 1jyWP#M#
--- 创建 备份数据的 device r4s R5p]|
USE master 8z-Td- R6
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 83a
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--- 开始 备份 9maw+ c!~
BACKUP DATABASE pubs TO testBack gyK"#-/_d
4、说明:创建新表 K*<n<;W
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 9=SZL~#CE
根据已有的表创建新表: [xC
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A:create table tab_new like tab_old (使用旧表创建新表) L{-w9(S`i
B:create table tab_new as select col1,col2... from tab_old definition only <5q }j-Q
5、说明:删除新表 PD?H5W3@
drop table tabname lV?SvXe
6、说明:增加一个列 lFcCWy
Alter table tabname add column col type KlPH.R3MPO
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。 jc<3\ 7
7、说明:添加主键: Alter table tabname add primary key(col) R&QT
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说明:删除主键: Alter table tabname drop primary key(col) 8/CGg_C1
8、说明:创建索引:create [unique] index idxname on tabname(col....) =
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删除索引:drop index idxname m8?(.BJ%
注:索引是不可更改的,想更改必须删除重新建。 *;m721#
9、说明:创建视图:create view viewname as select statement 'e)t+
删除视图:drop view viewname Wac8x%J
10、说明:几个简单的基本的sql语句 ZDf9Npe
选择:select * from table1 where 范围 wmIq{CXx,
插入:insert into table1(field1,field2) values(value1,value2) gLH(Wr~(a
删除:delete from table1 where 范围 NJp;t[v.^
更新:update table1 set field1=value1 where 范围 FueJe/~t
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! tL~|/C)d R
排序:select * from table1 order by field1,field2 [desc] y^
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总数:select count as totalcount from table1 [{ pc1U-
求和:select sum(field1) as sumvalue from table1 BK{8\/dg
平均:select avg(field1) as avgvalue from table1 .^uu*S_
最大:select max(field1) as maxvalue from table1 (<CLftQKg
最小:select min(field1) as minvalue from table1 ~(8A&!#,!
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11、说明:几个高级查询运算词 Rq7ks To
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A: UNION 运算符 =mZw71,
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。 /vMpSN|3
B: EXCEPT 运算符 c2C8}XJ|O
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。 g#AA.@/Z
C: INTERSECT 运算符 ~AO0(Lp
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。 |] YT6-?.
注:使用运算词的几个查询结果行必须是一致的。 (xTHin$
12、说明:使用外连接 $Z j.
A、left outer join: 5s>9v
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 A1C@'9R*
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c LF0~H}S;6B
B:right outer join: q\,H9/.0k
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 T:ck/:ZH
C:full outer join: 5HU>o|.
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 "*0
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二、提升 5Z:HCp-aG
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ZoUfQ!2*
法一:select * into b from a where 1<>1 l|K8+5L
法二:select top 0 * into b from a @sDd:>t
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) jK{MU) D+
insert into b(a, b, c) select d,e,f from b; !xvPG
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) CtfSfSAUuu
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 zQ[mO
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. GA|q[<U
4、说明:子查询(表名1:a 表名2:b) 1.!(#I3
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) k\lj<v<vD
5、说明:显示文章、提交人和最后回复时间 \!PC:+uJ
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b wqyAEVea'8
6、说明:外连接查询(表名1:a 表名2:b) ~t}:vGD j
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c BYY>;>V
7、说明:在线视图查询(表名1:a ) p|((r?{
select * from (SELECT a,b,c FROM a) T where t.a > 1; =4[zt^WX"
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 O []+v
select * from table1 where time between time1 and time2 qgDBu\
select a,b,c, from table1 where a not between 数值1 and 数值2 1$|z%(
9、说明:in 的使用方法 AL;"S;8
select * from table1 where a [not] in ('值1','值2','值4','值6') rQWft r^
10、说明:两张关联表,删除主表中已经在副表中没有的信息 {ys_uS{c*
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) kO.rgW82
11、说明:四表联查问题: ._yr7uY[M
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 ..... 0Zq"-
12、说明:日程安排提前五分钟提醒 HwcGbbX)
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 eAqQ~)8^
13、说明:一条sql 语句搞定数据库分页 l YhwV\3
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 O<Kr6+
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14、说明:前10条记录 n Au>i<
select top 10 * form table1 where 范围 Rl(b tr1w
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.) XBc+_=)$
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) }bHpFe
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 "mOoGy,(
(select a from tableA ) except (select a from tableB) except (select a from tableC) ]D%[GO//!
17、说明:随机取出10条数据 ;gc2vDMv
select top 10 * from tablename order by newid() o
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18、说明:随机选择记录 +n:#Uf)
select newid() @@5u{K
19、说明:删除重复记录 o{
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) X#o:-FKf
20、说明:列出数据库里所有的表名 &K4o8Qz
select name from sysobjects where type='U' vhg4E80Kr
21、说明:列出表里的所有的 8RK\B%UW
select name from syscolumns where id=object_id('TableName') QdRMp
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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。 JDP#tA3
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 JWBWa-
显示结果: s?2;u p*D
type vender pcs Ky DBCCOv
电脑 A 1 _ %P%~`?!
电脑 A 1 F 6Ol5
光盘 B 2 Ax\Fg
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光盘 A 2 %cv%u6 b
手机 B 3 g&[g?L
手机 C 3 ZN?(lt)u9
23、说明:初始化表table1 vQh'C.
TRUNCATE TABLE table1 %>bwpN
24、说明:选择从10到15的记录 xXbW6aI"
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc QQw^c1@
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三、技巧 A(uN=r@O
1、1=1,1=2的使用,在SQL语句组合时用的较多 <L`R!}
"where 1=1" 是表示选择全部 "where 1=2"全部不选, OJK/>
如: +VeLd+Q}
if @strWhere !='' crT[;w
begin 4[#.N
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere MhsG9q_%
end Qw^tzP8
else
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begin ?=vwr,ir
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' KIS.4nt#d"
end ]uZH 0
我们可以直接写成 v
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ^KlOD_GN|
2、收缩数据库 h~1QmEat
--重建索引 9W8Dp?:
DBCC REINDEX 8}0
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DBCC INDEXDEFRAG "~
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--收缩数据和日志 fG{oi(T
DBCC SHRINKDB 07#!b~N
DBCC SHRINKFILE :Y'nye3:
3、压缩数据库 p[wjHfIq
dbcc shrinkdatabase(dbname)
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4、转移数据库给新用户以已存在用户权限
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exec sp_change_users_login 'update_one','newname','oldname' .3!4@l\9C
go ^J G}|v3$
5、检查备份集 ks;%f34
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' (y36NH+
6、修复数据库 V~wmGp.e
ALTER DATABASE [dvbbs] SET SINGLE_USER %Xi%LUk{
GO (
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ooAZ,l=8
GO ]+Vcu zq/
ALTER DATABASE [dvbbs] SET MULTI_USER Pv'x|p*
GO l ghzd6
7、日志清除 ; YRZg|Zw
SET NOCOUNT ON k (R4-"@
DECLARE @LogicalFileName sysname, `MD/CFl4
@MaxMinutes INT, Fzu{,b
@NewSize INT ,&9|Ac?$
USE tablename -- 要操作的数据库名 5(W9J j]
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 3k/MigT
@MaxMinutes = 10, -- Limit on time allowed to wrap log. }8SHw|-
@NewSize = 1 -- 你想设定的日志文件的大小(M) 4EK[gM8
-- Setup / initialize $X?V_K;9/
DECLARE @OriginalSize int @|@43}M]C-
SELECT @OriginalSize = size t|q=NK/
FROM sysfiles }>w;
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WHERE name = @LogicalFileName d?K8Ygz
SELECT 'Original Size of ' + db_name() + ' LOG is ' + dO@iq^9-
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 9~_6mR<
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Gl:ASPZ6
FROM sysfiles x:x QXjJ
WHERE name = @LogicalFileName r3kI'I|bq
CREATE TABLE DummyTrans RoTT%c P_
(DummyColumn char (8000) not null) )t4C*+9<U
DECLARE @Counter INT, phdN9<Z
@StartTime DATETIME, c1^3lgPv
@TruncLog VARCHAR(255) p
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SELECT @StartTime = GETDATE(), +D@R'$N
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ?,NAihN]
DBCC SHRINKFILE (@LogicalFileName, @NewSize) oW_WW$+N
EXEC (@TruncLog) (nzt}i0
-- Wrap the log if necessary. V6k9L*VP
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired `et<Z
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) *v9G#[gG
AND (@OriginalSize * 8 /1024) > @NewSize [>0r'-kI
BEGIN -- Outer loop. +M*a.ra0OF
SELECT @Counter = 0 HL?pnT09
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) YV
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BEGIN -- update uv5@Alm
INSERT DummyTrans VALUES ('Fill Log') E;sltl
DELETE DummyTrans }FXRp=s
SELECT @Counter = @Counter + 1 3XRG"
END D6t]E)FH
EXEC (@TruncLog) RBXoU'.
END !=we7vK}
SELECT 'Final Size of ' + db_name() + ' LOG is ' + cMv3` $
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + UQFuEI<1-
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' @oEDtN
FROM sysfiles mm 8O
WHERE name = @LogicalFileName 7d)aDc*TjW
DROP TABLE DummyTrans *l//r
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SET NOCOUNT OFF Go|65Z\`7M
8、说明:更改某个表 m+g>s&1H
exec sp_changeobjectowner 'tablename','dbo' DkIFvsLK
9、存储更改全部表 9E^piLA
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Ba6xkEd
@OldOwner as NVARCHAR(128), UU/|s>F
@NewOwner as NVARCHAR(128) 4pqZ!@45|
AS AMdS+(J
DECLARE @Name as NVARCHAR(128) hs4r5[
DECLARE @Owner as NVARCHAR(128) *C BCQp[$
DECLARE @OwnerName as NVARCHAR(128) 7h2bL6Y88
DECLARE curObject CURSOR FOR <c#[.{A}s
select 'Name' = name, zCrcCr
'Owner' = user_name(uid) YO,ldsSz|r
from sysobjects W}RR_Gu
where user_name(uid)=@OldOwner *QG;KJ%
order by name s<b7/;w'
OPEN curObject 6,PLzZ5
FETCH NEXT FROM curObject INTO @Name, @Owner 3[0:,^a
WHILE(@@FETCH_STATUS=0) je-s%kNlJ
BEGIN Q1Ao65
if @Owner=@OldOwner l&B'.6XKs
begin ~}w 8UO
set @OwnerName = @OldOwner + '.' + rtrim(@Name) H~Cfni;
exec sp_changeobjectowner @OwnerName, @NewOwner ^=G+]$ 8
end 9x!y.gx
-- select @name,@NewOwner,@OldOwner _SqrQ
FETCH NEXT FROM curObject INTO @Name, @Owner 9[D7N
END YC'~8\x3z
close curObject @Hh"Y1B
deallocate curObject B}X#oA
GO e=jO_[
10、SQL SERVER中直接循环写入数据 5MJ'/Fy(
declare @i int "puz-W'n
set @i=1 R{_IrYk
while @i<30 ([~`{,sv
begin CCO g1X_
insert into test (userid) values(@i) SO/]d70HG
set @i=@i+1 pZxL?N!
end ; \+0H$
小记存储过程中经常用到的本周,本月,本年函数 *q{UipZbx
Dateadd(wk,datediff(wk,0,getdate()),-1) IJ;*N
Dateadd(wk,datediff(wk,0,getdate()),6) =Qrz|$_rv
Dateadd(mm,datediff(mm,0,getdate()),0) x(=x;X$[^
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) cmI#R1\
Dateadd(yy,datediff(yy,0,getdate()),0) 0
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 7p6J
上面的SQL代码只是一个时间段 JuSS5 _&
Dateadd(wk,datediff(wk,0,getdate()),-1) RZA\-?cO)
Dateadd(wk,datediff(wk,0,getdate()),6) *\", qMp
就是表示本周时间段. #cS,5(BM
下面的SQL的条件部分,就是查询时间段在本周范围内的: GwBQ
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) |T *qAJ8c
而在存储过程中 R:N-y."La.
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) +ctv]'P_
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) [[Z>(d$8