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。 g8w2Vz2/
$Bj;D=d@V
^2$ lJ
一、基础 ^=:9)CNw(
1、说明:创建数据库 *;m5'}jsy
CREATE DATABASE database-name :.?gHF.?
2、说明:删除数据库 om |"S
drop database dbname 4<cz--g
3、说明:备份sql server \mw(cM#:
--- 创建 备份数据的 device -0_d/'d
USE master IBQ@{QB
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' +&Hr4@pgW
--- 开始 备份 jMbC Y07v
BACKUP DATABASE pubs TO testBack o$[z],RO
4、说明:创建新表 !!4Qj
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) V^hE}`>z&
根据已有的表创建新表: ZVbl88,(l
A:create table tab_new like tab_old (使用旧表创建新表) e]T`ot#/
B:create table tab_new as select col1,col2... from tab_old definition only C=s1R;"H
5、说明:删除新表 !A>z(eIsv`
drop table tabname ?UK|>9y}Z
6、说明:增加一个列 lj{VL}R
Alter table tabname add column col type o/C\d$i'
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<03d~9|G
7、说明:添加主键: Alter table tabname add primary key(col) zOV=9"~{
说明:删除主键: Alter table tabname drop primary key(col) 2-"0 ^n{
8、说明:创建索引:create [unique] index idxname on tabname(col....) ;U<rc'qE
删除索引:drop index idxname Iw<j T|y)
注:索引是不可更改的,想更改必须删除重新建。 rz"txN
9、说明:创建视图:create view viewname as select statement w|CZ7|6
删除视图:drop view viewname sTOa
10、说明:几个简单的基本的sql语句 Qb!PRCHQ
选择:select * from table1 where 范围 N<QjdD&
插入:insert into table1(field1,field2) values(value1,value2) &AlJ "N|
删除:delete from table1 where 范围 ?7M.o
更新:update table1 set field1=value1 where 范围 *loOiM\5a
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! -F=v6N {
排序:select * from table1 order by field1,field2 [desc] @xeAc0.^
总数:select count as totalcount from table1 iA0q_( \X
求和:select sum(field1) as sumvalue from table1 mo1oyQg8
平均:select avg(field1) as avgvalue from table1 nOQa_G]Gz
最大:select max(field1) as maxvalue from table1 zNY)'
最小:select min(field1) as minvalue from table1 _{Sm k[
h Xb%;GL
Qfky_5R\
T]j.=|,d
11、说明:几个高级查询运算词 Wd0[%`dq
.`7cBsXH
d/}SAvtt
A: UNION 运算符 etd&..]J
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。 *26334B.R
B: EXCEPT 运算符 {CR 5K9
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。 16L]=&@
C: INTERSECT 运算符 50
A^bbid
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。 T \CCF
注:使用运算词的几个查询结果行必须是一致的。 >Bs#Xb_B]
12、说明:使用外连接 %lX%8Z$v
A、left outer join: k"g._|G
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 G[8in
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 49d@!
B:right outer join: K_
lVISBQ
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 `fNG$ODL
C:full outer join: t6BHGX{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。 \`, [)`
bsd99-_(4
-!0_:m3
二、提升 kNT}dv]<
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) VyRsPg[(
法一:select * into b from a where 1<>1 v4RlLgdS%
法二:select top 0 * into b from a x+]!m/
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) BC,.^"fA6
insert into b(a, b, c) select d,e,f from b; peJKNX.!q
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) '+
xu#R
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 [xh*"wT#g
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. >HPdzLY?
4、说明:子查询(表名1:a 表名2:b) DAg58
=qJ
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) RNPbH.
5、说明:显示文章、提交人和最后回复时间 N$xtHtz8"
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b SxK:]Aw
6、说明:外连接查询(表名1:a 表名2:b) Z_gC&7+
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c (Y+N@d
7、说明:在线视图查询(表名1:a ) (~$/$%b
select * from (SELECT a,b,c FROM a) T where t.a > 1; m~lpyAw
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 ?<Y+peu
select * from table1 where time between time1 and time2 p#SY /KIw
select a,b,c, from table1 where a not between 数值1 and 数值2 U$H@ jJ*
9、说明:in 的使用方法 # wc \T
select * from table1 where a [not] in ('值1','值2','值4','值6') ^FZ^6*
10、说明:两张关联表,删除主表中已经在副表中没有的信息 w'X]M#Q><
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) oo=#XZkk
11、说明:四表联查问题: *_ +7ni
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 ..... Gn)y>
AN
12、说明:日程安排提前五分钟提醒 "lNzGi-H
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ]I/Vb s
13、说明:一条sql 语句搞定数据库分页 M0|'f'
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 hUz[uyt
14、说明:前10条记录 N$TL;T>
select top 10 * form table1 where 范围 ^`SA'F,
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) [TF8'jI0
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ^uS/r#l
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 OG3/-K 8R
(select a from tableA ) except (select a from tableB) except (select a from tableC) q8:{Nk
17、说明:随机取出10条数据 tRw@U4=y
select top 10 * from tablename order by newid() X%bFN
18、说明:随机选择记录 0t#g}
select newid() ]O{u tm
19、说明:删除重复记录 .Hc(y7HV
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) okq[ o90
20、说明:列出数据库里所有的表名 \V2,pi8'v
select name from sysobjects where type='U' g\GdkiIj
21、说明:列出表里的所有的 H0a/(4/xg
select name from syscolumns where id=object_id('TableName') i)Lp7m z
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 [!^-J}^g~\
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type q{die[J
显示结果: *2}O-e
type vender pcs ;eigOU]
电脑 A 1 \n9A^v`F/
电脑 A 1 _{jP;W
光盘 B 2 sA9&/p/
光盘 A 2 -ng=l;
手机 B 3 19(Dj&x
手机 C 3 >x3ug]Bu
23、说明:初始化表table1 DWt*jX *
TRUNCATE TABLE table1 4$,,Ppn
24、说明:选择从10到15的记录 qQxz(}REu9
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 0aR,H[r[?
JK#vkCkyM
Ufo>|A6;$
5FC4@Ms`
三、技巧 2JmZ{
1、1=1,1=2的使用,在SQL语句组合时用的较多 JNWg|Qt
"where 1=1" 是表示选择全部 "where 1=2"全部不选, K?#]("De6
如: ,pK|SL
if @strWhere !='' NHw x:-RH
begin gM>=%/.
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 4z:#I;
end `ya;:$(6
else 6@tvRDeaDW
begin Ni*Wz*o
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' .BO<
end RA a[t :|
我们可以直接写成 kqvow3u
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere W[NEe,.>
2、收缩数据库 RV-h IdAU
--重建索引 ? 81X
DBCC REINDEX ,pq{& A
DBCC INDEXDEFRAG R*1kR|*_)
--收缩数据和日志 *jzLFuWIG
DBCC SHRINKDB /T0nLp`gi
DBCC SHRINKFILE K#K\-TR|$
3、压缩数据库 K:yr-#(P/
dbcc shrinkdatabase(dbname) y?30_#[dN
4、转移数据库给新用户以已存在用户权限 L6
6-LMkH
exec sp_change_users_login 'update_one','newname','oldname' +TN9ujL6@
go tJ&5tNl
5、检查备份集 A%Z)wz{
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 7s'- +~
6、修复数据库 $e\N+~KNCy
ALTER DATABASE [dvbbs] SET SINGLE_USER %@ mGK8
GO i(2y:U3[@
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Z\>, ),O
GO cJn HW
ALTER DATABASE [dvbbs] SET MULTI_USER mnF}S5[9
GO P\~{3U
7、日志清除 ]*%+H|l
SET NOCOUNT ON f?Bj _z
DECLARE @LogicalFileName sysname, 1
[z'G)v
@MaxMinutes INT, `GQ{*_-
@NewSize INT RE46k`44
USE tablename -- 要操作的数据库名 6R}j-1
<n
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 a0Oe:]mo\
@MaxMinutes = 10, -- Limit on time allowed to wrap log. -E&e1u,Mi
@NewSize = 1 -- 你想设定的日志文件的大小(M) |bZM/U=
-- Setup / initialize m.%`4L^`T
DECLARE @OriginalSize int m8R=?U~!S
SELECT @OriginalSize = size XOb}<y)r~
FROM sysfiles H!IDV}dn
WHERE name = @LogicalFileName %4>x!{jwV
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ~hN~>0O
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 83]PA<R
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' sLcY,AH
FROM sysfiles Y'"N"$n'_
WHERE name = @LogicalFileName +1{fzb>9_
CREATE TABLE DummyTrans ;Fl<v@9
(DummyColumn char (8000) not null) cep$_Ja
DECLARE @Counter INT, ~waNPjPRG
@StartTime DATETIME, M<8ML!N0;t
@TruncLog VARCHAR(255) )JgC$ <
SELECT @StartTime = GETDATE(), |qjZ38;6
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 3"
Vd==oK~
DBCC SHRINKFILE (@LogicalFileName, @NewSize) A{,n;;
EXEC (@TruncLog) LZ~`29qw(
-- Wrap the log if necessary. ~o15#Pfn/
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired T|'&K:[TJ
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) l\q}
|o
AND (@OriginalSize * 8 /1024) > @NewSize )ctr"&-
BEGIN -- Outer loop. >w'$1tc?+F
SELECT @Counter = 0 %l9$a`&
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000))
7
Yv!N
BEGIN -- update mv
Ov<x;l
INSERT DummyTrans VALUES ('Fill Log') ~I_owCVZ
DELETE DummyTrans 8<PKKDgbfd
SELECT @Counter = @Counter + 1 E[Bo4?s&^
END k&s; {|!
EXEC (@TruncLog) E'dX)J9e$/
END V7<eQ0;m
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ;[5r7
jHU
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + k
'zat3#f
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ,-#GX{!
FROM sysfiles `<vxG4=62\
WHERE name = @LogicalFileName we]>(|
DROP TABLE DummyTrans o42`z>~
SET NOCOUNT OFF H7IW"UkBR
8、说明:更改某个表 {7#03 k
exec sp_changeobjectowner 'tablename','dbo' WfVMdwz=
9、存储更改全部表 !L\'Mk/=A
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch -}<g-*m"q
@OldOwner as NVARCHAR(128), SPwPCI1?
@NewOwner as NVARCHAR(128) O*7i }\{
AS 9D4-^M:a
DECLARE @Name as NVARCHAR(128) !=zx
DECLARE @Owner as NVARCHAR(128) *6*-WV6
DECLARE @OwnerName as NVARCHAR(128) 79ZxqvB\
DECLARE curObject CURSOR FOR c4] u&tvjJ
select 'Name' = name, ;L6Xs_L~
'Owner' = user_name(uid) L$JI43HZ
from sysobjects .9 kyrlm
where user_name(uid)=@OldOwner h[U7!aM
order by name j@P5(3r
OPEN curObject Di.;<v#FL
FETCH NEXT FROM curObject INTO @Name, @Owner o~~ 9!\
WHILE(@@FETCH_STATUS=0) \graMu}-
BEGIN 5H.Db
if @Owner=@OldOwner %x2b0L\g
begin )/%S=c
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 84`rbL!M
exec sp_changeobjectowner @OwnerName, @NewOwner
GXeAe}T
end HF4Lqh'oco
-- select @name,@NewOwner,@OldOwner s-6:N9-
FETCH NEXT FROM curObject INTO @Name, @Owner jH0Bo;
END 1xC`ZhjcD
close curObject J:};n@<
deallocate curObject ,ep9V,+|
GO ;X7i/DQ
10、SQL SERVER中直接循环写入数据 j.&
;c'V$.
declare @i int >h7$v~nra
set @i=1
T&/_e
while @i<30 nLd~2qBuv
begin &z ksRX
insert into test (userid) values(@i) 5P\N"Yjx'
set @i=@i+1 _;G=G5r
end iwo$\
小记存储过程中经常用到的本周,本月,本年函数 ~07RFR
Dateadd(wk,datediff(wk,0,getdate()),-1) NhDA7z`b'J
Dateadd(wk,datediff(wk,0,getdate()),6) 4K,''7N3
Dateadd(mm,datediff(mm,0,getdate()),0) #WEq-0L
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) kIM
C~Z
Dateadd(yy,datediff(yy,0,getdate()),0) tR O IBq|
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) d
Uz<1^L
上面的SQL代码只是一个时间段 uGCtLA+sL
Dateadd(wk,datediff(wk,0,getdate()),-1) ]L(54q;W
Dateadd(wk,datediff(wk,0,getdate()),6) ,wTg$g-$
就是表示本周时间段. B/_6Ieb+
下面的SQL的条件部分,就是查询时间段在本周范围内的: EIK*49b2
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 6+ANAk
而在存储过程中 {Q<0\`A
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) %BICt @E
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) h#O"Q+J9n