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。 vWmp?m
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一、基础 I)yaR+l
1、说明:创建数据库 }O+xs3Uv
CREATE DATABASE database-name iPl,KjGk
2、说明:删除数据库 <xSh13<
drop database dbname &-FG}|*4M
3、说明:备份sql server =c\(]xX
--- 创建 备份数据的 device f|(9+~K/7&
USE master Il4]1d|
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' MOh&1]2j5
--- 开始 备份 9b >+ehj B
BACKUP DATABASE pubs TO testBack P !f{U;B
4、说明:创建新表 q}p$S2`
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) _O}U4aGMTC
根据已有的表创建新表: w_>\Yd [
A:create table tab_new like tab_old (使用旧表创建新表) r'nPP6`
B:create table tab_new as select col1,col2... from tab_old definition only pf'DbY!
5、说明:删除新表 -zYa@PW
drop table tabname 3.Mpd
6、说明:增加一个列 s@$0!8sxm
Alter table tabname add column col type D(Rr<-(
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 V+D5<nICr
7、说明:添加主键: Alter table tabname add primary key(col) >'Lkn2WI
说明:删除主键: Alter table tabname drop primary key(col) UH0l8ixc
8、说明:创建索引:create [unique] index idxname on tabname(col....) {,uSDIOj$
删除索引:drop index idxname rb@[Edj
注:索引是不可更改的,想更改必须删除重新建。 wz3X;1l`c
9、说明:创建视图:create view viewname as select statement Uu8ayN j
删除视图:drop view viewname d)U(XiK'
10、说明:几个简单的基本的sql语句 | eCVq(R
选择:select * from table1 where 范围 UTE6U6
插入:insert into table1(field1,field2) values(value1,value2) 4jDi3MMU9
删除:delete from table1 where 范围 yw:%)b{
更新:update table1 set field1=value1 where 范围 xU%]G.k
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 6<@+J
排序:select * from table1 order by field1,field2 [desc] 9c4p9b!
总数:select count as totalcount from table1 >lM/\HO2
求和:select sum(field1) as sumvalue from table1 {hN\=_6*EW
平均:select avg(field1) as avgvalue from table1 m4h)Wq
最大:select max(field1) as maxvalue from table1 An#[
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最小:select min(field1) as minvalue from table1 Y?1T
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11、说明:几个高级查询运算词 v+x rnz
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A: UNION 运算符 [4C_iaE
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。 2k=|p@V n~
B: EXCEPT 运算符 Has}oe[
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。 ^L.I9a#]
C: INTERSECT 运算符 6oQ7u90z*
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`$qcEw
注:使用运算词的几个查询结果行必须是一致的。 'LG\]h>+)
12、说明:使用外连接 aC=2v7*
A、left outer join: !Z>,dN
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。 #tUhul/O
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 bA0H
B:right outer join: ORKJy)*"
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。 9$U>St
C:full outer join: zqU$V~5;rG
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。 }\H. G
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二、提升 <,p$eQ)T%
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) #O~pf[[L
法一:select * into b from a where 1<>1 VJ'-"8tY&
法二:select top 0 * into b from a &FRf-6/
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) }8l+Jd3"
insert into b(a, b, c) select d,e,f from b; 0Y* "RbG
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) c"knzB vy
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 /|NyO+Io
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. c99|+i50
4、说明:子查询(表名1:a 表名2:b) XFs7kTY
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3)
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5、说明:显示文章、提交人和最后回复时间 _}j>
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b =>>Dnp
6、说明:外连接查询(表名1:a 表名2:b) f#AuZ]h
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c :T PG~`k(
7、说明:在线视图查询(表名1:a ) J
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select * from (SELECT a,b,c FROM a) T where t.a > 1; LjGLi>kI~
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 GCQOjqiR
select * from table1 where time between time1 and time2 HL[V}m
select a,b,c, from table1 where a not between 数值1 and 数值2 S.iUiS"
9、说明:in 的使用方法 `ba<eT':
select * from table1 where a [not] in ('值1','值2','值4','值6') >op/<?<
10、说明:两张关联表,删除主表中已经在副表中没有的信息 NR&a
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) tMU10=d
11、说明:四表联查问题: @>'Wiq!
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... S9[Up}`
12、说明:日程安排提前五分钟提醒 ?5Z-w
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 HW_2!t_R
13、说明:一条sql 语句搞定数据库分页 8 rE`
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 bg9_$laDi
14、说明:前10条记录 X_JC1
select top 10 * form table1 where 范围 O.Dz}[w
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.) bZK`]L[
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) P*Jk 8MK#G
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 .ozBa778u
(select a from tableA ) except (select a from tableB) except (select a from tableC) >d
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17、说明:随机取出10条数据 uU$/4{
select top 10 * from tablename order by newid() ](-[
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18、说明:随机选择记录 R(y`dQy<K
select newid() nx`W!|g$`
19、说明:删除重复记录 lr)MySsu#H
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) <.lN'i;(
20、说明:列出数据库里所有的表名 t':*~b{V@7
select name from sysobjects where type='U' 70*yx?T V
21、说明:列出表里的所有的 &SZAe/3+
select name from syscolumns where id=object_id('TableName') {Xpjm6a7
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。 \(f82kv
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 ]Zay9jD}c-
显示结果: )"P.n-aF
type vender pcs Z^A( Q>{e
电脑 A 1 hI<$lEB
电脑 A 1 T8T,G4Q
光盘 B 2 _mQ~[}y+?
光盘 A 2 {![E)~
手机 B 3 bDw\;bnG
手机 C 3 |QH )A
23、说明:初始化表table1 z} VCiS0
TRUNCATE TABLE table1 B%[#["Ol
24、说明:选择从10到15的记录 +C`vO5\0
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc { iLr$89
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三、技巧 0j#$Swa
1、1=1,1=2的使用,在SQL语句组合时用的较多 L<<v
"where 1=1" 是表示选择全部 "where 1=2"全部不选, N9Fu
如: HwMe^e;
if @strWhere !='' u*Y!=IT
begin TSL/zTLDJ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 3@;24X
end [.G~5%974
else Q6X}R,KA1
begin .$x822
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' <&M5#:u
end [z}$G:s
我们可以直接写成 99q$>nx,w
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ,n5 [Y)
2、收缩数据库 &19z|Id
--重建索引 ON_GD"
DBCC REINDEX ]=0D~3o3
DBCC INDEXDEFRAG '_=XfTF
--收缩数据和日志 !Nhq)i
DBCC SHRINKDB b{e|~v6&
DBCC SHRINKFILE 97!VH>MX
3、压缩数据库 5i3nz=~o
dbcc shrinkdatabase(dbname) T:j!a{_|
4、转移数据库给新用户以已存在用户权限 pHDPj,lu
exec sp_change_users_login 'update_one','newname','oldname' n lvDMZ
go TU8K\;l]
5、检查备份集 `p^xdj}
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' a)L=+Z
6、修复数据库 yF&?gPh&
ALTER DATABASE [dvbbs] SET SINGLE_USER K)8 m?sf/
GO 2-wvL&pi)
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK l]e7
GO !jJH}o/KW
ALTER DATABASE [dvbbs] SET MULTI_USER na4^RPtN\e
GO Y2p~chx9
7、日志清除 g!;Hv
SET NOCOUNT ON q/tC/V%@(
DECLARE @LogicalFileName sysname, 2ld0w=?+eu
@MaxMinutes INT, kObgoMT<[
@NewSize INT b9Ix*!Y
USE tablename -- 要操作的数据库名 5adB5)`
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 %1]Lc=[j
@MaxMinutes = 10, -- Limit on time allowed to wrap log. PmE2T\{s!
@NewSize = 1 -- 你想设定的日志文件的大小(M) N(&/ Ud
-- Setup / initialize &_c5C
DECLARE @OriginalSize int {7q +3f <
SELECT @OriginalSize = size myY@Wp
FROM sysfiles {5:V
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WHERE name = @LogicalFileName 3WdANR
SELECT 'Original Size of ' + db_name() + ' LOG is ' + B7qiCX}pD
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + lT]dj9l
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' </d&bS
FROM sysfiles Rh#TR"
WHERE name = @LogicalFileName EabZ7zFoN
CREATE TABLE DummyTrans aib)ItNb
(DummyColumn char (8000) not null) OK9D4
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DECLARE @Counter INT, Os7 3u#!'
@StartTime DATETIME, ODqWXw#
@TruncLog VARCHAR(255) 6JL:p{RLi
SELECT @StartTime = GETDATE(), v:]
AS:
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' !tD,phca~
DBCC SHRINKFILE (@LogicalFileName, @NewSize) YVLaO*(f
EXEC (@TruncLog) V0WFh=CM@
-- Wrap the log if necessary. t[L'}ig!q
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired wq&TU'O
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) KEj-y+
AND (@OriginalSize * 8 /1024) > @NewSize Z)zmT%t
BEGIN -- Outer loop. [HhdeLOX
SELECT @Counter = 0 U~8 oE_+
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Z66@@?`
BEGIN -- update S}*%l)vfR
INSERT DummyTrans VALUES ('Fill Log') @=[SsS
DELETE DummyTrans ^E8eW
SELECT @Counter = @Counter + 1 M e
END f)+fdc
EXEC (@TruncLog) L$+ap~ld
END SW%d'1ya
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 9WuKW***
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + zZ=.riK
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' :xT=uE.I
FROM sysfiles Ls^$E
WHERE name = @LogicalFileName =2eG j'}
DROP TABLE DummyTrans e$^ O_e
SET NOCOUNT OFF Ci
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8、说明:更改某个表 ;-d :!*
exec sp_changeobjectowner 'tablename','dbo' M-df Gk
9、存储更改全部表 }A"%YDrNbG
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch LJMw-#61sj
@OldOwner as NVARCHAR(128), }0Q6iHX@
@NewOwner as NVARCHAR(128) k w!1]N
AS 0: (@Y
DECLARE @Name as NVARCHAR(128) Q
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DECLARE @Owner as NVARCHAR(128) $fY4amX6Z
DECLARE @OwnerName as NVARCHAR(128) rX#}2
DECLARE curObject CURSOR FOR ` 0k
select 'Name' = name, LPk85E
'Owner' = user_name(uid) \TrhJ
from sysobjects ~WJEH#
where user_name(uid)=@OldOwner @BN cIJk9
order by name q<b;xx
OPEN curObject (k..ll p~
FETCH NEXT FROM curObject INTO @Name, @Owner J,E'F!{
WHILE(@@FETCH_STATUS=0) +'x`rk
BEGIN xla9:*pPn
if @Owner=@OldOwner toEmIa~o6
begin 'qhA4W9
set @OwnerName = @OldOwner + '.' + rtrim(@Name) }cE,&n
exec sp_changeobjectowner @OwnerName, @NewOwner /tf}8d
end ,g$N
-- select @name,@NewOwner,@OldOwner ET`;TfqM
FETCH NEXT FROM curObject INTO @Name, @Owner X] /r'Tz
END s Hu~;)
close curObject 4PEJ}BW
deallocate curObject ~J6c1jG
GO dt
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10、SQL SERVER中直接循环写入数据 Ss&R!w9p
declare @i int jv]:`$}G\
set @i=1 rK2*DuE
while @i<30 4
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begin $N=A, S
insert into test (userid) values(@i) G~e`O,+
set @i=@i+1 g!O(@Sqp1
end m4*Rr
小记存储过程中经常用到的本周,本月,本年函数 E#T-2^nD
Dateadd(wk,datediff(wk,0,getdate()),-1) ?zN v7Bj
Dateadd(wk,datediff(wk,0,getdate()),6) (+ 9_nAgZ,
Dateadd(mm,datediff(mm,0,getdate()),0) lV^sVN Z]
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) xgt dmv%
Dateadd(yy,datediff(yy,0,getdate()),0) Tp`by
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ('xu2 ;<
上面的SQL代码只是一个时间段 'wX'}3_/g
Dateadd(wk,datediff(wk,0,getdate()),-1) h2u>CXD
Dateadd(wk,datediff(wk,0,getdate()),6) ~OEP)c\k
就是表示本周时间段. g0^%X9s
下面的SQL的条件部分,就是查询时间段在本周范围内的: G)?O!(_
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 0QDm3V0n
而在存储过程中 0bpl3Fh.v
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Db=
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) k"V3FXC)