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。 [>>_%T\I
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一、基础 !YpH\wUyvP
1、说明:创建数据库 8&HBR #
CREATE DATABASE database-name ;F-
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2、说明:删除数据库 ~$>JYJj
drop database dbname H!0m8LCnb
3、说明:备份sql server EdqB4-#7
--- 创建 备份数据的 device %CYo,
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USE master uv-O`)
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' )H]L/n
--- 开始 备份 F5+FO^3E
BACKUP DATABASE pubs TO testBack x>mI$K(6M
4、说明:创建新表 7bbFUUUG"
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) /~s<@<1!X
根据已有的表创建新表: q2F`q. j
A:create table tab_new like tab_old (使用旧表创建新表) \z6UWZ
B:create table tab_new as select col1,col2... from tab_old definition only {S+?n[1r\
5、说明:删除新表 &/Gn!J;1
drop table tabname ~9APc{"A
6、说明:增加一个列 I74Rw*fB
Alter table tabname add column col type bBc<p{
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。 4Dn&+=fq
7、说明:添加主键: Alter table tabname add primary key(col) 4 a&8G
说明:删除主键: Alter table tabname drop primary key(col) d0}(d Gl
8、说明:创建索引:create [unique] index idxname on tabname(col....) "y*3p0E
删除索引:drop index idxname At[Q0'jkc
注:索引是不可更改的,想更改必须删除重新建。 aaf}AIL.
9、说明:创建视图:create view viewname as select statement .czUJyFms}
删除视图:drop view viewname 6q'Q?Uw^
10、说明:几个简单的基本的sql语句 0+1!-Wo
选择:select * from table1 where 范围 Vb#a ,t
插入:insert into table1(field1,field2) values(value1,value2) 68bvbig
删除:delete from table1 where 范围 Q[#8ErUY
更新:update table1 set field1=value1 where 范围 l=T;hk
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! f^hJA Z
排序:select * from table1 order by field1,field2 [desc] u"oO._a(
总数:select count as totalcount from table1 gfN=0Xj4
求和:select sum(field1) as sumvalue from table1 b'SP,}s5"
平均:select avg(field1) as avgvalue from table1 3^&`E}r
最大:select max(field1) as maxvalue from table1 k ?6d\Q
最小:select min(field1) as minvalue from table1 SXl~lYUL
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11、说明:几个高级查询运算词 -Wmb
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A: UNION 运算符 s&o9LdL
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。 I:oEt
B: EXCEPT 运算符 Ebj0 {ZL
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。 1 Vc_jYO@
C: INTERSECT 运算符 ECM#J28D
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。 VFF5Tp
注:使用运算词的几个查询结果行必须是一致的。 j+-`P5
12、说明:使用外连接 2/t; }pw8
A、left outer join: j>\rs|^O
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。 Z@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 cs\=8_5
B:right outer join: t 3N}):
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@#5
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C:full outer join: (i(E~^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。 n7~3~i`D;
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二、提升 _hl| 3
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用)
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法一:select * into b from a where 1<>1 `EMGrw_
法二:select top 0 * into b from a \fC;b"j
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) bG"FN/vg
insert into b(a, b, c) select d,e,f from b; r|ZB3L|7
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) $$0<
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 DC> R
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. RJ0,7E<B
4、说明:子查询(表名1:a 表名2:b) W!.FnM5x
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) }oG6XI9
5、说明:显示文章、提交人和最后回复时间 iNi1+sm
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b LzLJ6A>;R
6、说明:外连接查询(表名1:a 表名2:b) ]Z\ W%'q+
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c l}-k>fug
7、说明:在线视图查询(表名1:a ) ,MJddbcg
select * from (SELECT a,b,c FROM a) T where t.a > 1; [cEGkz
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 9'~qA(=.?
select * from table1 where time between time1 and time2 8/)q$zs
select a,b,c, from table1 where a not between 数值1 and 数值2 |zfFB7}v
9、说明:in 的使用方法 S?i^ ~
select * from table1 where a [not] in ('值1','值2','值4','值6') tAep_GR
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Cb<7?),vK
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) @V^.eVM\R
11、说明:四表联查问题: $U7/w?gc'
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... sVP\EF8PY
12、说明:日程安排提前五分钟提醒 gzVZPvTPE
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 (O09HY:
13、说明:一条sql 语句搞定数据库分页 N
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select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 bvZD@F`2
14、说明:前10条记录 Zp_j\B
select top 10 * form table1 where 范围 RaTNA W)v>
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) NW0se
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 3"0QW4A
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 b0h\l#6
(select a from tableA ) except (select a from tableB) except (select a from tableC) [X@{xF^vBQ
17、说明:随机取出10条数据 af6<w.i
select top 10 * from tablename order by newid() CiHx.5TiC
18、说明:随机选择记录 #WG;p(?:
select newid() 3K~^H1l
19、说明:删除重复记录 D1>*ml
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) @|ZUyat
20、说明:列出数据库里所有的表名 b|x B<
select name from sysobjects where type='U' x%@M*4:&
21、说明:列出表里的所有的 GadY#]}(
select name from syscolumns where id=object_id('TableName') V#b*:E.cA
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 <x;g9Z>(
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type jM6$R1HX
显示结果: F+R1}5-3cl
type vender pcs ZT/f
电脑 A 1 W"#<r
电脑 A 1 W6EEC<$JL
光盘 B 2 twldwuN
光盘 A 2 !}U3{L-
手机 B 3 x7l}u`N4
手机 C 3 6OC4?#96%'
23、说明:初始化表table1 sP@XV/`3L6
TRUNCATE TABLE table1 8aRmHy"9l
24、说明:选择从10到15的记录 }mZCQJ#`
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ^_G#JJ\@$
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三、技巧 =w _T{V
1、1=1,1=2的使用,在SQL语句组合时用的较多 qa~ju\jm.
"where 1=1" 是表示选择全部 "where 1=2"全部不选, /#_[{lSr?
如: *qL2=2
if @strWhere !='' }/NjZ*u
begin p.4Sgeh#
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere $ <[r3
end ;*Y+. ?>a
else t*BCpC}
begin *) \y52z
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 5$Kv%U
end x3Fn'+
我们可以直接写成 GP^^
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Eqny'44
2、收缩数据库 %(?;`
--重建索引 ?_S);
DBCC REINDEX {ByKTx&
DBCC INDEXDEFRAG #|:q"l9
--收缩数据和日志 [!KsAsmk
DBCC SHRINKDB *}(B"FSO
DBCC SHRINKFILE E'8XXV^I?P
3、压缩数据库 !.@:t`w
dbcc shrinkdatabase(dbname) FRPdfo37
4、转移数据库给新用户以已存在用户权限 T DPQ+Kg_
exec sp_change_users_login 'update_one','newname','oldname' G6Wa0Z
go g;o5m}
5、检查备份集 k-s|gC4
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' cqZlpm$c
6、修复数据库 Zmk 9C@
ALTER DATABASE [dvbbs] SET SINGLE_USER c(3idO*R)
GO *$('ous8
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK yswf2F
GO 0_^3
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ALTER DATABASE [dvbbs] SET MULTI_USER <7ag=IgDy
GO NgxJz
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7、日志清除 \Z~@/OVc
SET NOCOUNT ON Pa|*Jcr
DECLARE @LogicalFileName sysname, >K%+h)%kI
@MaxMinutes INT, 4 l+z
@NewSize INT V%M@zd?u.
USE tablename -- 要操作的数据库名 Iz#jR2:yn
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 JGzEm>_m
@MaxMinutes = 10, -- Limit on time allowed to wrap log. T`I4_x
@NewSize = 1 -- 你想设定的日志文件的大小(M) cZ.p
-- Setup / initialize ^q}phj3E
DECLARE @OriginalSize int &;vMJ
SELECT @OriginalSize = size )T(1oK(g
FROM sysfiles V2 ;?
WHERE name = @LogicalFileName pnv)D}"
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ESS1 L$y
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 8jky-r
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' uAk>VPuuZ
FROM sysfiles ?6MUyH]a
WHERE name = @LogicalFileName 1F2(MKOo!
CREATE TABLE DummyTrans gI Gi7x
(DummyColumn char (8000) not null) KAr5>^<zw
DECLARE @Counter INT, 6TQ[2%X'
@StartTime DATETIME, vsq
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@TruncLog VARCHAR(255) [NGq$5
SELECT @StartTime = GETDATE(), 4*q6#=G
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' VjiwW%UOM
DBCC SHRINKFILE (@LogicalFileName, @NewSize) \)g}
EXEC (@TruncLog) eM7F8j
-- Wrap the log if necessary. >v/%R~BuX
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired UD2l!)rW
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) _*t75e$-
AND (@OriginalSize * 8 /1024) > @NewSize H5gcP11r
BEGIN -- Outer loop. xWWVU}fd1
SELECT @Counter = 0 T+5H2]yy)
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ronZa0
BEGIN -- update E.x<J.[Y
INSERT DummyTrans VALUES ('Fill Log') `P;3,@
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DELETE DummyTrans =$kSn\L,
SELECT @Counter = @Counter + 1 ~>%% kQt
END cS#| _
EXEC (@TruncLog) RS{E|
END vcOw`oS
SELECT 'Final Size of ' + db_name() + ' LOG is ' + j#VR>0oC]\
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + P$/Y9o
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 9.Sv"=5gz
FROM sysfiles #Y'ub
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WHERE name = @LogicalFileName 91FVe
DROP TABLE DummyTrans 1HRcEzA
SET NOCOUNT OFF ae+*gkPv8
8、说明:更改某个表 P[ ,
exec sp_changeobjectowner 'tablename','dbo' 8(-N;<Ef2
9、存储更改全部表 D<^K7tJui
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch hi ),PfAV
@OldOwner as NVARCHAR(128), \Dx)P[Ur
@NewOwner as NVARCHAR(128) X&%;(`
AS 7"])Y
DECLARE @Name as NVARCHAR(128) "(;t`,F
DECLARE @Owner as NVARCHAR(128) P`n"E8"ab<
DECLARE @OwnerName as NVARCHAR(128) //}KWz
DECLARE curObject CURSOR FOR 3pkx3tp{
select 'Name' = name, mGUG
'Owner' = user_name(uid) wqt/0,\
from sysobjects |f[:mO
where user_name(uid)=@OldOwner 2&<&q J
order by name -
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OPEN curObject M9(Kxux#
FETCH NEXT FROM curObject INTO @Name, @Owner Vf$q3X
WHILE(@@FETCH_STATUS=0) &WVRh=R
BEGIN W=!D[G R
if @Owner=@OldOwner 1KI5tf>>p
begin 3hR3)(+1
set @OwnerName = @OldOwner + '.' + rtrim(@Name) >6z7.d
exec sp_changeobjectowner @OwnerName, @NewOwner )KN]"<jB
end h]^=
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-- select @name,@NewOwner,@OldOwner =#?=Lh
FETCH NEXT FROM curObject INTO @Name, @Owner t,yMO
END D{]9s
close curObject CN#2-[T
deallocate curObject T'%Rkag>
GO k=.pcDX
10、SQL SERVER中直接循环写入数据 IU rGJ#}O
declare @i int jbu+>
set @i=1 :h<QM$P<
while @i<30 f_r4*#&v
begin 7p Zd?-6M^
insert into test (userid) values(@i) l]geQl:7`r
set @i=@i+1 ^A t,x
end &jF[f4:7
小记存储过程中经常用到的本周,本月,本年函数 (=QiXX1r
Dateadd(wk,datediff(wk,0,getdate()),-1) G-RE
Dateadd(wk,datediff(wk,0,getdate()),6) t",b.vki\z
Dateadd(mm,datediff(mm,0,getdate()),0) ]Cc8[ZC
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) od]1:8OF
Dateadd(yy,datediff(yy,0,getdate()),0) !;&{Q^}
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) MZ<BCRB
上面的SQL代码只是一个时间段 PA${<wyBR_
Dateadd(wk,datediff(wk,0,getdate()),-1) +C`zI~8
Dateadd(wk,datediff(wk,0,getdate()),6) R"{oj]d;$F
就是表示本周时间段. 6w$pL(
下面的SQL的条件部分,就是查询时间段在本周范围内的: j:J7
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) M{`uI8vD
而在存储过程中 #j6qq3OG
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) _n!W4zwi
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Q+^ "v]V`d