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。 TQ{Han!
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一、基础 =e gW
1、说明:创建数据库 8}fu,$$5
CREATE DATABASE database-name 05snuNt]-
2、说明:删除数据库 iJZ/jCI
drop database dbname +V{7")px6
3、说明:备份sql server 8E4mA5@
--- 创建 备份数据的 device `2`\]X_A{
USE master ] )F7)
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' @BrMl%gV
--- 开始 备份 x7vctjM|
BACKUP DATABASE pubs TO testBack u`olW%C/T
4、说明:创建新表 Q>R>R*1.j
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) F29va
根据已有的表创建新表: E@-KGsdhK
A:create table tab_new like tab_old (使用旧表创建新表) %e`$p=m
B:create table tab_new as select col1,col2... from tab_old definition only 5Q 'i2*j
5、说明:删除新表 zfwS
drop table tabname &BtK($
6、说明:增加一个列 N.4q.
Alter table tabname add column col type vjQb%/LWl
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。 ?Q-h n:F)
7、说明:添加主键: Alter table tabname add primary key(col) mk3_
说明:删除主键: Alter table tabname drop primary key(col) /;tPNp{!dw
8、说明:创建索引:create [unique] index idxname on tabname(col....) wWSdTLX
删除索引:drop index idxname K{ \;2M
注:索引是不可更改的,想更改必须删除重新建。 `E!N9qI?t$
9、说明:创建视图:create view viewname as select statement "Vr[4&`
删除视图:drop view viewname 7lS#f1E
10、说明:几个简单的基本的sql语句 p/2jh&
选择:select * from table1 where 范围 9_QP !,
插入:insert into table1(field1,field2) values(value1,value2) A8q;q 2
删除:delete from table1 where 范围 2MATpV#BT
更新:update table1 set field1=value1 where 范围 0vVV%,v
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! {0;3W7
排序:select * from table1 order by field1,field2 [desc] iSFuT7;%
总数:select count as totalcount from table1 m$9w"8R
求和:select sum(field1) as sumvalue from table1 f+|$&p%
平均:select avg(field1) as avgvalue from table1 quvanxV-L
最大:select max(field1) as maxvalue from table1 8E8N6
最小:select min(field1) as minvalue from table1 !q-f9E4`
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11、说明:几个高级查询运算词 -F=v6N {
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A: UNION 运算符 mo1oyQg8
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。 nOQa_G]Gz
B: EXCEPT 运算符 zNY)'
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。 _{Sm k[
C: INTERSECT 运算符 rU;RGz6}
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。 r1<F
注:使用运算词的几个查询结果行必须是一致的。 }BiiE%a
12、说明:使用外连接 Ja SI^go
A、left outer join: Oky**B[D'
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。 ,ZQZ}`x(
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 <BO)E(
B:right outer join: rJa$9B*^
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 16L]=&@
C:full outer join: 50
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全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 T \CCF
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二、提升 k"g._|G
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) G[8in
法一:select * into b from a where 1<>1 49d@!
法二:select top 0 * into b from a K_
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) `fNG$ODL
insert into b(a, b, c) select d,e,f from b; t6BHGX{o
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) \`, [)`
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 bsd99-_(4
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. -!0_:m3
4、说明:子查询(表名1:a 表名2:b) kNT}dv]<
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) VyRsPg[(
5、说明:显示文章、提交人和最后回复时间 v4RlLgdS%
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b x+]!m/
6、说明:外连接查询(表名1:a 表名2:b) S!PzLTc
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c be e5
7、说明:在线视图查询(表名1:a ) /T,Z>R
select * from (SELECT a,b,c FROM a) T where t.a > 1; RUr=fEH
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 []0mX70N
select * from table1 where time between time1 and time2 /)xlJUq
select a,b,c, from table1 where a not between 数值1 and 数值2 QZX~T|Ckv
9、说明:in 的使用方法 BS&;n
select * from table1 where a [not] in ('值1','值2','值4','值6') Cda!Mk:
10、说明:两张关联表,删除主表中已经在副表中没有的信息 );*YQmdx'
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) `MEYd U1
11、说明:四表联查问题: 8?*RIA.a
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 ..... R.LL#u};
12、说明:日程安排提前五分钟提醒 m%"uPv\
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 pq:7F
13、说明:一条sql 语句搞定数据库分页 0wFH!s/B
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 #q3l!3\mW
14、说明:前10条记录 k z"3ZDR
select top 10 * form table1 where 范围 Y%|@R3[Nk
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.) eUl/o1~mXa
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) l{VSb92f
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 'xv8Gwf"
(select a from tableA ) except (select a from tableB) except (select a from tableC) =&!HwOnp
17、说明:随机取出10条数据 tA$)cg+.
select top 10 * from tablename order by newid() ~^^ NHq
18、说明:随机选择记录 .)|a2d ~F
select newid()
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19、说明:删除重复记录 |0{u->+ )
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) jKZt~I
20、说明:列出数据库里所有的表名 YF:2>w<
select name from sysobjects where type='U' h;V,n
21、说明:列出表里的所有的 w[_x(Ojq;
select name from syscolumns where id=object_id('TableName') =SD\Q!fA
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。 \<vNVz7.D
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 fbFX4?-
显示结果: hI pKJ&hm
type vender pcs F?m?UQS'u
电脑 A 1 zq1mmFIO
电脑 A 1 hh~n#7w~IR
光盘 B 2 FuX 8v
光盘 A 2 dY"}\v6
手机 B 3 $|KaBx1
手机 C 3 Pv<FLo%u<
23、说明:初始化表table1 M+wt__vHf
TRUNCATE TABLE table1 +pH@oFNK
24、说明:选择从10到15的记录 \Hqc9&0
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc n:U>Fj>q
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三、技巧 WxbsD S;
1、1=1,1=2的使用,在SQL语句组合时用的较多 6|J'>)
"where 1=1" 是表示选择全部 "where 1=2"全部不选, P6Bl
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如: 6zIgQ4Bp24
if @strWhere !='' *m+5Pr`7
begin U-0#0} _
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere HNa]H;-+5
end NYABmI/0c
else Ip}Vb6}
begin &X`u9 V
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 5j"1z1_&
end SbsouGD,{
我们可以直接写成 'mdM q=VI
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 4c~>ci,N?(
2、收缩数据库 kqvow3u
--重建索引 <-UOISyf
DBCC REINDEX J
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DBCC INDEXDEFRAG n,P5o_^:
--收缩数据和日志 iy\KzoB
DBCC SHRINKDB :9l51oE7
DBCC SHRINKFILE \g-j9|0
3、压缩数据库 ,`td@Y
dbcc shrinkdatabase(dbname) LF*Q!
4、转移数据库给新用户以已存在用户权限 Oajv^H,Em
exec sp_change_users_login 'update_one','newname','oldname' %Hi~aRz
go BbJkdt7
5、检查备份集 v|
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ^T4Ay=~{
6、修复数据库 2
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ALTER DATABASE [dvbbs] SET SINGLE_USER h5|.Et
GO +rNkN:/L
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK TrE3S'EU#R
GO YpdNX.P,
ALTER DATABASE [dvbbs] SET MULTI_USER FM^9}*
GO HTz+K6&
7、日志清除 c\cZ]RZ
SET NOCOUNT ON P\~{3U
DECLARE @LogicalFileName sysname, ]*%+H|l
@MaxMinutes INT, f?Bj _z
@NewSize INT q]4pEip
USE tablename -- 要操作的数据库名 K2'O]#
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 eIPG#A
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ~@I@} n
@NewSize = 1 -- 你想设定的日志文件的大小(M) p4X{"Z\mn
-- Setup / initialize =G-N`
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DECLARE @OriginalSize int 1M%S
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SELECT @OriginalSize = size }4%/pOi:f
FROM sysfiles W^g[L:s
WHERE name = @LogicalFileName OCyG_DLT$5
SELECT 'Original Size of ' + db_name() + ' LOG is ' + !UV5zmS
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + N:+
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ),@f6](
FROM sysfiles /k:$l9C[
WHERE name = @LogicalFileName 83]PA<R
CREATE TABLE DummyTrans 00vBpsZj2;
(DummyColumn char (8000) not null) b_$1f>
DECLARE @Counter INT, qFRdg V>8
@StartTime DATETIME, 96|[}:+$&:
@TruncLog VARCHAR(255) y@vj;3:
SELECT @StartTime = GETDATE(), 2%rLoL$Y2+
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' j033%p+Xc
DBCC SHRINKFILE (@LogicalFileName, @NewSize) p{;i& HNdp
EXEC (@TruncLog) <"&'>?8j
-- Wrap the log if necessary. t
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired oJ;rc{n-
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 0.(<'!"y
AND (@OriginalSize * 8 /1024) > @NewSize Z/ bB
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BEGIN -- Outer loop. utO.WfWP
SELECT @Counter = 0 V+B71\x<
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) KI&:9j+M)
BEGIN -- update *FgJ|y6gk
INSERT DummyTrans VALUES ('Fill Log') >w'$1tc?+F
DELETE DummyTrans %l9$a`&
SELECT @Counter = @Counter + 1
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END ZykrQ\q9
EXEC (@TruncLog) z[!x:# q8`
END 18!VO4u\I
SELECT 'Final Size of ' + db_name() + ' LOG is ' + )Id2GV~2B
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 2wh#$zGy
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' X:q_c =X
FROM sysfiles o<VP'F{p
WHERE name = @LogicalFileName cqL(^R.
DROP TABLE DummyTrans E'dX)J9e$/
SET NOCOUNT OFF 6* rcR]
8、说明:更改某个表 `ti8-
exec sp_changeobjectowner 'tablename','dbo' delf
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9、存储更改全部表 L`K;IV%;
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch VQ
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@OldOwner as NVARCHAR(128), M'jXve(=yF
@NewOwner as NVARCHAR(128) Q</h-skLZ
AS E8[XG2ye
DECLARE @Name as NVARCHAR(128) r?p{LF
DECLARE @Owner as NVARCHAR(128) juno.$
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DECLARE @OwnerName as NVARCHAR(128) 3o8\/-*<
DECLARE curObject CURSOR FOR Cv TwBJy1
select 'Name' = name, `^8*<+
'Owner' = user_name(uid) |XcH]7Ai"
from sysobjects -zC]^Ho@
where user_name(uid)=@OldOwner hLuJWjCV
order by name T1~)^qQ
OPEN curObject #\FT EY!
FETCH NEXT FROM curObject INTO @Name, @Owner Gt^d;7x]
WHILE(@@FETCH_STATUS=0) pt!'v$G/*
BEGIN |>utWT]S
if @Owner=@OldOwner L$JI43HZ
begin h[U7!aM
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 6v47 QW|'
exec sp_changeobjectowner @OwnerName, @NewOwner O-GxUHwWr
end %Y',|+Arx
-- select @name,@NewOwner,@OldOwner nm):SEkC
FETCH NEXT FROM curObject INTO @Name, @Owner !
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END :EB,{|m
close curObject dB)[O9K)
deallocate curObject k,_i#9X
GO `jW4H$D
10、SQL SERVER中直接循环写入数据 do'ORcZ
declare @i int !C`20,U
set @i=1 +i)AS0?d
while @i<30 $%He$t
begin ,f<B}O
insert into test (userid) values(@i) ^
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set @i=@i+1 (+MC<J/i
end M_&4]\PkCy
小记存储过程中经常用到的本周,本月,本年函数 VD;j[~/Z
Dateadd(wk,datediff(wk,0,getdate()),-1) #]zhZW4
Dateadd(wk,datediff(wk,0,getdate()),6) W8*
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Dateadd(mm,datediff(mm,0,getdate()),0) BJIQ
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 0zV 4`y
Dateadd(yy,datediff(yy,0,getdate()),0) Ar`\ N1a
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Mo|yv[(K,
上面的SQL代码只是一个时间段 jsWX 6(=
Dateadd(wk,datediff(wk,0,getdate()),-1) YN^jm
Dateadd(wk,datediff(wk,0,getdate()),6) on50+)uN
就是表示本周时间段. J#@lV
下面的SQL的条件部分,就是查询时间段在本周范围内的: zPBfiK_hV
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) .eTk=i[N-
而在存储过程中 okDJ(AIV+
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) wP`sXPSmIu
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) coAW9=o}