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?*f}J
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一、基础 nz/cs n
1、说明:创建数据库 nR,QqIFFw
CREATE DATABASE database-name }Rq{9j,%
2、说明:删除数据库 /kqa|=-`q
drop database dbname xH>j
3、说明:备份sql server 4@9xq<<5
--- 创建 备份数据的 device eY`o=xN
USE master Hw,@oOh.
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' l-8rCaq&J
--- 开始 备份 :d|~k
BACKUP DATABASE pubs TO testBack 3
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4、说明:创建新表 R-Gg= l5
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) V17!~
根据已有的表创建新表: L1QDA}6?_Y
A:create table tab_new like tab_old (使用旧表创建新表) $OaxetPH
B:create table tab_new as select col1,col2... from tab_old definition only =A_fL{ SM
5、说明:删除新表 (~?p`g+I.P
drop table tabname "6i3'jc`
6、说明:增加一个列 OgCz[QXr_
Alter table tabname add column col type |}o3EX
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。 AK&=/[U>
7、说明:添加主键: Alter table tabname add primary key(col) 6P02=
说明:删除主键: Alter table tabname drop primary key(col) PeJIa
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8、说明:创建索引:create [unique] index idxname on tabname(col....) !WTL:dk
删除索引:drop index idxname &&
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注:索引是不可更改的,想更改必须删除重新建。 :c9 H2
9、说明:创建视图:create view viewname as select statement X?'pcYSL
删除视图:drop view viewname ]3L/8]:
10、说明:几个简单的基本的sql语句 }qBmt>#
选择:select * from table1 where 范围 5I/lF oy7
插入:insert into table1(field1,field2) values(value1,value2) fN6n2*wr(
删除:delete from table1 where 范围 "Ve9\$_s
更新:update table1 set field1=value1 where 范围 $-paYQ4
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! a[E}o<{
排序:select * from table1 order by field1,field2 [desc] 1/J6<FVq
总数:select count as totalcount from table1 j7J'd?l
求和:select sum(field1) as sumvalue from table1 nPUD6<bF
平均:select avg(field1) as avgvalue from table1 #cqI0ny?G
最大:select max(field1) as maxvalue from table1 I
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最小:select min(field1) as minvalue from table1 NJg )S2]7
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11、说明:几个高级查询运算词 /z: mi
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A: UNION 运算符 XmN8S_M>v
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ;KT5qiqYH
B: EXCEPT 运算符 &W{v(@
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 wJh/tb=$o
C: INTERSECT 运算符 ?HeUU
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。 <,y> W!
注:使用运算词的几个查询结果行必须是一致的。
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12、说明:使用外连接 XfN(7d0
A、left outer join: ^95njE`>t`
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。 E[<*Al+N
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 l_Zx'm
B:right outer join: ^ U~QQ
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。 gmZ] E45
C:full outer join: \85~~v@
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。 664D5f#EJ
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二、提升 9T0g%&
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) *NC@o*
法一:select * into b from a where 1<>1 #@F.wV0
法二:select top 0 * into b from a &_74h);2I:
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ~yJJ00%
insert into b(a, b, c) select d,e,f from b; w@LLxL>Y
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) Gr#WD=I-}
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ;3o7>yEv
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. <6X*k{
4、说明:子查询(表名1:a 表名2:b) e0hY
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) w1eFm:'
5、说明:显示文章、提交人和最后回复时间 n/S+0uT
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 8#/y`ul
6、说明:外连接查询(表名1:a 表名2:b) G=|~SYz
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c oXUb_/
7、说明:在线视图查询(表名1:a ) L+}<gQJ(
select * from (SELECT a,b,c FROM a) T where t.a > 1; LL==2KNUo
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 w/*m_O\!
select * from table1 where time between time1 and time2 5GGO:
select a,b,c, from table1 where a not between 数值1 and 数值2 1x%B`d
9、说明:in 的使用方法
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select * from table1 where a [not] in ('值1','值2','值4','值6') n}c~+0`un
10、说明:两张关联表,删除主表中已经在副表中没有的信息 gU1Pb]]
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) L@Q+HN
11、说明:四表联查问题: 8 [D"
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 ..... qw{`?1[+
12、说明:日程安排提前五分钟提醒 x_r*<?OZ
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 hw(\3h()
13、说明:一条sql 语句搞定数据库分页 B<0Kl.V
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 Sb(OG 6
14、说明:前10条记录 h}kJ,n
select top 10 * form table1 where 范围 ;%;||?'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.) F~eY'~&H}
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) -+0kay%
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 (>NZYPw^3
(select a from tableA ) except (select a from tableB) except (select a from tableC) r-.>3J
17、说明:随机取出10条数据 YrV@k*O*
select top 10 * from tablename order by newid() d</F6aM\
18、说明:随机选择记录 nv\K!wZI=b
select newid() Qqs1%u;e8
19、说明:删除重复记录 h~ZLULW)B
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) uqLP$At
20、说明:列出数据库里所有的表名 7*"Jx}eM
select name from sysobjects where type='U' 5JHEBw5W%
21、说明:列出表里的所有的 y
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select name from syscolumns where id=object_id('TableName') !#=3>\np+X
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。 P^tTg
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 u@CQ+pnf:(
显示结果: l qKj;'
type vender pcs !-%XrU8o3
电脑 A 1 " m13HS
电脑 A 1 keFH
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光盘 B 2 2t
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光盘 A 2 {Ay dt8
手机 B 3 "%p7ft
手机 C 3 T^(> 8/O
23、说明:初始化表table1 L#zD4L
TRUNCATE TABLE table1 9bspf {
24、说明:选择从10到15的记录 2TNK
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc kDI?v6y5
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三、技巧 cvG*p||
1、1=1,1=2的使用,在SQL语句组合时用的较多 6)7cw8^
"where 1=1" 是表示选择全部 "where 1=2"全部不选, B(k tIy
如: @&Bh!_TWc
if @strWhere !='' 4QTHBT+2`
begin 0^sY>N"
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere f 9Kt>2IN
end %S'+x[4W
else b?c/J{me
begin U7?v4O]D[
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 0Qq<h;8xEc
end .ESvMK~x
我们可以直接写成 >0W
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere %qiVbm0
2、收缩数据库 +vaA
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--重建索引 8'%m!
DBCC REINDEX G!;PV^6x
DBCC INDEXDEFRAG S_/S2(V"
--收缩数据和日志 Cs7ol-\)
DBCC SHRINKDB se`Eez}
DBCC SHRINKFILE ~> Q9
3、压缩数据库 ,G g;:)k\
dbcc shrinkdatabase(dbname) 9)NKI02M|
4、转移数据库给新用户以已存在用户权限 EK Vcz'w
exec sp_change_users_login 'update_one','newname','oldname' 0%dOi
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go N2"B\
5、检查备份集 bd~m'cob>
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' kS8?N`2}LV
6、修复数据库 6(rN(C
ALTER DATABASE [dvbbs] SET SINGLE_USER T7^;!;i`X
GO `Z8k#z'bN
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK e6Y>Bk
GO t>/x-{bH\
ALTER DATABASE [dvbbs] SET MULTI_USER )*>wa%[-q
GO cw{TS
7、日志清除 \yC /OLXq
SET NOCOUNT ON 0o"aSCq8t
DECLARE @LogicalFileName sysname, #79[Qtkrhm
@MaxMinutes INT, k$JOHru
@NewSize INT *LU/3H|}
USE tablename -- 要操作的数据库名 q]I aRho
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Dzf\m>H[
@MaxMinutes = 10, -- Limit on time allowed to wrap log. PXkpttIE]M
@NewSize = 1 -- 你想设定的日志文件的大小(M) )Wr_*>xj
-- Setup / initialize !Yv_V]u=
DECLARE @OriginalSize int UaF~[toX
SELECT @OriginalSize = size {MSE}|A\V
FROM sysfiles 4P k%+l
WHERE name = @LogicalFileName XFvl
SELECT 'Original Size of ' + db_name() + ' LOG is ' + L_RVHvA=M/
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 6UuN-7z!"
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' HFZ'xp|3dn
FROM sysfiles tVEe) QX
WHERE name = @LogicalFileName {0Y6jk>I
CREATE TABLE DummyTrans $_E.D>5^%7
(DummyColumn char (8000) not null) k#Sr; "
DECLARE @Counter INT, /HpM17
@StartTime DATETIME, +tT"
@TruncLog VARCHAR(255) } &B6
SELECT @StartTime = GETDATE(), ypx~WXFK
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' W.MZN4=
DBCC SHRINKFILE (@LogicalFileName, @NewSize) [
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EXEC (@TruncLog) e;"J,7@
-- Wrap the log if necessary. E|"SMA,
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired KE~Q88s
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) YHQ]]#'
AND (@OriginalSize * 8 /1024) > @NewSize 3HpqMz
BEGIN -- Outer loop. CTRUr"
SELECT @Counter = 0 r)pt(*KHo
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) -smN}*3[
BEGIN -- update J<QZ)<T,&
INSERT DummyTrans VALUES ('Fill Log') 95z|}16UK
DELETE DummyTrans 1>j,v+
SELECT @Counter = @Counter + 1 *k62Qz3
END u,So+%
EXEC (@TruncLog) *VsVCUCz5*
END RI&O@?+U
SELECT 'Final Size of ' + db_name() + ' LOG is ' + P'lnS&yA
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + t-iXY0%&
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' b;UBvwY_
FROM sysfiles tfGs|x
WHERE name = @LogicalFileName $G9LaD#;M
DROP TABLE DummyTrans AAlc %d/9
SET NOCOUNT OFF f?Zjd&|Ch
8、说明:更改某个表 p{^:b6
exec sp_changeobjectowner 'tablename','dbo' 4 k<o
9、存储更改全部表 @)6b
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ^EX"fRwNi
@OldOwner as NVARCHAR(128), ES&u*X:
@NewOwner as NVARCHAR(128) 7qB4_
AS 1"ZtE\{
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DECLARE @Name as NVARCHAR(128) .Rk8qRB
DECLARE @Owner as NVARCHAR(128) LBCH7@V1yR
DECLARE @OwnerName as NVARCHAR(128) >nghFm
DECLARE curObject CURSOR FOR S@HC$
select 'Name' = name, uI7n{4W*x
'Owner' = user_name(uid) w~b:9_reY
from sysobjects $:F+Nf
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where user_name(uid)=@OldOwner OX]$Xdb2:
order by name _M%S
OPEN curObject ~4{q
FETCH NEXT FROM curObject INTO @Name, @Owner "kyCY9)%
WHILE(@@FETCH_STATUS=0) iAu/ t
BEGIN O@T,!_Zf
if @Owner=@OldOwner q>2bkc GY#
begin Z)`)9]*
set @OwnerName = @OldOwner + '.' + rtrim(@Name) o{sv<$
exec sp_changeobjectowner @OwnerName, @NewOwner xR0T'@q
end
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-- select @name,@NewOwner,@OldOwner t^~vi'bB
FETCH NEXT FROM curObject INTO @Name, @Owner @./h$]6
END H~+A6g]T
close curObject ~i5YqH0
deallocate curObject 4f[%Bb
GO 1l$Ei,9
10、SQL SERVER中直接循环写入数据 >9&31wA_
declare @i int u[b |QR=5
set @i=1 p@^G)x
while @i<30 \sAaVdZJH(
begin wsWFD xR
insert into test (userid) values(@i) {=ox1+d
set @i=@i+1 W7qh1}_%
end oZvG Kf
小记存储过程中经常用到的本周,本月,本年函数 4`5yrCd
Dateadd(wk,datediff(wk,0,getdate()),-1) )R JEOl1
Dateadd(wk,datediff(wk,0,getdate()),6) q*&R&K;q
Dateadd(mm,datediff(mm,0,getdate()),0) t>\sP
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) a_>|Ny6{
Dateadd(yy,datediff(yy,0,getdate()),0) 5g7@Dj,.
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) b"h'7 C/
上面的SQL代码只是一个时间段 *U[yeE].
Dateadd(wk,datediff(wk,0,getdate()),-1) @Dh2@2`>
Dateadd(wk,datediff(wk,0,getdate()),6) FOXSs8"c]!
就是表示本周时间段. LORcf 1X/
下面的SQL的条件部分,就是查询时间段在本周范围内的: ,2S!$M
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ]c/E7|0Q
而在存储过程中 ]
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) t WI-
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) AoS7B:T;!