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。 TJ_6:;4,|_
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一、基础 pYu6[
1、说明:创建数据库 /L5:/Z
CREATE DATABASE database-name q_mxZM
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2、说明:删除数据库 3-)}.8F
drop database dbname uPxjW"M+
3、说明:备份sql server DL,]iJm
--- 创建 备份数据的 device TIR Is1
USE master (<-m|H};
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ll- KK`Ka
--- 开始 备份 mEkYT
BACKUP DATABASE pubs TO testBack w`3.wALb
4、说明:创建新表 (d
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) eT ]*c?"
根据已有的表创建新表: =dQ/^C_hj
A:create table tab_new like tab_old (使用旧表创建新表) 4\g[&
B:create table tab_new as select col1,col2... from tab_old definition only ;DVg[#
5、说明:删除新表 m|t\w|B2
drop table tabname i1A<0W|
6、说明:增加一个列 ?r5a*
Alter table tabname add column col type r.6?|
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。 ,"{e$|iY
7、说明:添加主键: Alter table tabname add primary key(col) (/!@
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说明:删除主键: Alter table tabname drop primary key(col) L/I ]
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8、说明:创建索引:create [unique] index idxname on tabname(col....) U@{>+G[
删除索引:drop index idxname K[
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注:索引是不可更改的,想更改必须删除重新建。 n2Mpo\2
9、说明:创建视图:create view viewname as select statement <RY!Mc
删除视图:drop view viewname (TO<SY3AB
10、说明:几个简单的基本的sql语句 (I'{
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选择:select * from table1 where 范围 0>]&9'cn
插入:insert into table1(field1,field2) values(value1,value2) -m mQ]'.0
删除:delete from table1 where 范围 ,8d&uR}x
更新:update table1 set field1=value1 where 范围 64`l?F
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! C>mFylN
排序:select * from table1 order by field1,field2 [desc] EAKW^'D
总数:select count as totalcount from table1 B., BP
求和:select sum(field1) as sumvalue from table1 3Co1bY:
平均:select avg(field1) as avgvalue from table1 s0/m qZ]s
最大:select max(field1) as maxvalue from table1 2tCw{Om*
最小:select min(field1) as minvalue from table1 VB T66kV
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11、说明:几个高级查询运算词 1uR@ZK
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A: UNION 运算符 F:[[@~z
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。 @
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B: EXCEPT 运算符 s{V&vRr
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。 8Q{9AoQ3'
C: INTERSECT 运算符 &0:Gj3`
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。 U5@B7v1
注:使用运算词的几个查询结果行必须是一致的。 \u(Gj]B#"
12、说明:使用外连接 v0tFU!Q%
A、left outer join: dLwP7#r
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。 4mEJu
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 Gm=&[?}
B:right outer join: l @@pXg3
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。 F MYcZ+4
C:full outer join: rd$T6!I
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。 PxvxZJf$@
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二、提升 b9 li
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) <w8H[y"c
法一:select * into b from a where 1<>1 6c/0OM#
法二:select top 0 * into b from a Cw kQhj?
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) f~TkU\Rh
insert into b(a, b, c) select d,e,f from b; 2Ur&_c6P
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) /h`gQyGuY
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ]n<Ba7Y
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. oWi#?'
4、说明:子查询(表名1:a 表名2:b) X%fLV(
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) S1'?"zAmd
5、说明:显示文章、提交人和最后回复时间 CRrEs
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b IB 4L(n1
6、说明:外连接查询(表名1:a 表名2:b) 1p&=tN
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c =?wDQ:
7、说明:在线视图查询(表名1:a ) QR8]d1+GV
select * from (SELECT a,b,c FROM a) T where t.a > 1; ,@f |t&
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 W$J.B!O
select * from table1 where time between time1 and time2 h^`@%g9 S
select a,b,c, from table1 where a not between 数值1 and 数值2 MBKF8b'k
9、说明:in 的使用方法 kApD D[ N
select * from table1 where a [not] in ('值1','值2','值4','值6') /Dt:4{aTOC
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ui|6ih$+
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) _4#7 ? p
11、说明:四表联查问题: 9Av{>W?
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... u(?U[pe[
12、说明:日程安排提前五分钟提醒 0o BAJP
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 qNrLM!Rj
13、说明:一条sql 语句搞定数据库分页 Fl{~#]
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 xy$aFPH!-
14、说明:前10条记录 a\Gd;C ^`
select top 10 * form table1 where 范围 Nl%5OBm
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.) 5INw#1~
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) +>[zn
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 vS3Y9|-:
(select a from tableA ) except (select a from tableB) except (select a from tableC) V$Oj@vI
17、说明:随机取出10条数据 U7f
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select top 10 * from tablename order by newid() `zl,|}u)
18、说明:随机选择记录 g}a+%Obb
select newid() ?@`5^7*
19、说明:删除重复记录 $*P+
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) h4Arg~Or
20、说明:列出数据库里所有的表名 lU&2K$`
select name from sysobjects where type='U' 9(vp`Z8B4
21、说明:列出表里的所有的 "SWL@}8vx
select name from syscolumns where id=object_id('TableName') ,nP nH1vb
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。 n-qle5s j
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 YZnFU( j
显示结果: -y?ve od#
type vender pcs 0QrRG$<4X
电脑 A 1 R3)ccom
电脑 A 1 AxTFVot
光盘 B 2 yOb']
光盘 A 2 mRGr+m
手机 B 3 nKtRJ,>
手机 C 3 {BaPK&x,
23、说明:初始化表table1 =T?Xph{
TRUNCATE TABLE table1 i??+5o@uTF
24、说明:选择从10到15的记录 ymqn1ja1
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc O<Ay`p5
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三、技巧 s+G(N$0U
1、1=1,1=2的使用,在SQL语句组合时用的较多 dpt P(H
"where 1=1" 是表示选择全部 "where 1=2"全部不选, (r}StR+
如: J\'f5)k
if @strWhere !='' bS55/M w
begin ^U,C])n
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere fmUrwI1 %
end ^r7KEeVD
else 29|nt1Z
begin gS]
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' aE"dpYQ
end Pmr'W\aIR
我们可以直接写成 '9<8<d7?
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere r4K%dx-t
2、收缩数据库 fJ\u8
--重建索引 q%/.+g2-\
DBCC REINDEX ('d,Sh
DBCC INDEXDEFRAG JlEfUg#*
--收缩数据和日志 ;4v`FC>
DBCC SHRINKDB R /_vJHI
DBCC SHRINKFILE $!z .[GL
3、压缩数据库 P(C5@x(Z
dbcc shrinkdatabase(dbname) Tpkt'|8
4、转移数据库给新用户以已存在用户权限 G#uB%:)&0u
exec sp_change_users_login 'update_one','newname','oldname' @KZW*-"
go EF=5[$
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5、检查备份集 wp4
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' "tpD ->
6、修复数据库 "l#"c{ee{
ALTER DATABASE [dvbbs] SET SINGLE_USER ^hT2ed +
GO rploQF~OFF
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK S'@Ok=FSy
GO MBQ|*}+;
ALTER DATABASE [dvbbs] SET MULTI_USER G1ruF8
GO k<N5*k8M
7、日志清除 0YoV`D,U
SET NOCOUNT ON '^_^o)0gp
DECLARE @LogicalFileName sysname, j*1MnP3/8Y
@MaxMinutes INT, ^ ~Tn[w W_
@NewSize INT X~\O]
USE tablename -- 要操作的数据库名 n 4H'FZ
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 =~)rT8+)
@MaxMinutes = 10, -- Limit on time allowed to wrap log. iT{[zLz>1
@NewSize = 1 -- 你想设定的日志文件的大小(M) I;, n|o
-- Setup / initialize *F(<:3;2
DECLARE @OriginalSize int u`!Dp$P
SELECT @OriginalSize = size ~=otdJ
FROM sysfiles #D>:'ezm
WHERE name = @LogicalFileName FZ8Qj8
SELECT 'Original Size of ' + db_name() + ' LOG is ' + c+whpQ=01
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + wp:Zur5Y
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' #AO}JP
FROM sysfiles "Z dI~
WHERE name = @LogicalFileName TKEcbGhy
CREATE TABLE DummyTrans YXdo&'Q<qX
(DummyColumn char (8000) not null) ?D_}',Wx
DECLARE @Counter INT, 0+w(cf~6
@StartTime DATETIME, gh^w
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@TruncLog VARCHAR(255) C!^;%VQ}d
SELECT @StartTime = GETDATE(), =i/r:
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ]{ch]m
DBCC SHRINKFILE (@LogicalFileName, @NewSize) AB<bW3qf(
EXEC (@TruncLog) N\CHIsVm>
-- Wrap the log if necessary. nmuU*oL
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired AOTtAV_e
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ?PV@WrU>B
AND (@OriginalSize * 8 /1024) > @NewSize 'CG% PjCO
BEGIN -- Outer loop. "`a,/h'
SELECT @Counter = 0 )$*B
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) vP%:\u:{
BEGIN -- update rQpQqBu
INSERT DummyTrans VALUES ('Fill Log') f&$$*a
DELETE DummyTrans jD6T2K7i
SELECT @Counter = @Counter + 1 +p]@ b
END 'S=eW_ 0/
EXEC (@TruncLog) w2r*$Q
END ,1vFX$
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 2xBh
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 7p{uRSE4._
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ]2[\E~^KU
FROM sysfiles B.gEV*@
WHERE name = @LogicalFileName ;L%\[H>G
DROP TABLE DummyTrans =xb/zu(
SET NOCOUNT OFF IiX2O(*ZE
8、说明:更改某个表 `)BZk[64
exec sp_changeobjectowner 'tablename','dbo' 9wdX#=I
9、存储更改全部表 0p\Kf(|E*6
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch IZd~Am3f
@OldOwner as NVARCHAR(128), A43[i@o
@NewOwner as NVARCHAR(128) Kc>Rd
AS p DU+(A4>
DECLARE @Name as NVARCHAR(128) VArMFP)cz
DECLARE @Owner as NVARCHAR(128) )"E1/$*k
DECLARE @OwnerName as NVARCHAR(128) cf%2A1I2W
DECLARE curObject CURSOR FOR zYftgH_o
select 'Name' = name, #!r>3W&
'Owner' = user_name(uid) FIQHs"#T
from sysobjects (^<skx>
where user_name(uid)=@OldOwner =#&+w[4?&.
order by name X7MA>j3m
OPEN curObject T@n};,SQ
FETCH NEXT FROM curObject INTO @Name, @Owner /<o?T{z<-
WHILE(@@FETCH_STATUS=0) /-=h|A#Kh
BEGIN V.ae 5@;
if @Owner=@OldOwner &u(pBr8B
begin 8Qkwg]X
set @OwnerName = @OldOwner + '.' + rtrim(@Name) O}6*9Xy
exec sp_changeobjectowner @OwnerName, @NewOwner C7&L9k~jf
end &.Yu%=}
-- select @name,@NewOwner,@OldOwner ~D/1U)kt
FETCH NEXT FROM curObject INTO @Name, @Owner b~TTz`HZ
END A[:(#iR5-E
close curObject ~cfvL*~5
deallocate curObject \GGyz{i
GO SUsdX[byb
10、SQL SERVER中直接循环写入数据 _0Y?(}
declare @i int }0OQm?xh
set @i=1 S*WLb/R2
while @i<30 '\"5qB
begin 81)i>]
insert into test (userid) values(@i) @U =~c9
set @i=@i+1 gaE8\JSr
end [o
6
小记存储过程中经常用到的本周,本月,本年函数 J@ 8OU
Dateadd(wk,datediff(wk,0,getdate()),-1) %+C6#cj
Dateadd(wk,datediff(wk,0,getdate()),6) pM*(
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Dateadd(mm,datediff(mm,0,getdate()),0) RiIafiaD
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) >#Bu [nD%
Dateadd(yy,datediff(yy,0,getdate()),0) 71\GK
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 2=naPTP(
上面的SQL代码只是一个时间段 uaha)W;'9
Dateadd(wk,datediff(wk,0,getdate()),-1) nM99AW
Dateadd(wk,datediff(wk,0,getdate()),6) C!Fi &~
就是表示本周时间段. Xpfw2;`U'
下面的SQL的条件部分,就是查询时间段在本周范围内的: Z[1|('
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) _gl1Qtv@rf
而在存储过程中 J!@R0U.
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) t&_X{!1X"w
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) &(|x-OT