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。 >
6=3y4tP
F)Z9Qlo
,6o tm
一、基础 "d/uyS$6
1、说明:创建数据库 =LgMG^@mu
CREATE DATABASE database-name +zXcTT[V
2、说明:删除数据库 nrX+ '
drop database dbname i r'C(zD=
3、说明:备份sql server '&2-{Y [!
--- 创建 备份数据的 device 27}7
n
USE master Z~}9^ (qc
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' &|#,Bsk"@
--- 开始 备份 TKiYEh
BACKUP DATABASE pubs TO testBack 0F.S[!I
4、说明:创建新表 <@lj\,
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 6L)7Q0Z
根据已有的表创建新表: H/.UDz
A:create table tab_new like tab_old (使用旧表创建新表) N1.fV -
B:create table tab_new as select col1,col2... from tab_old definition only >;R7r|^k
5、说明:删除新表 F/[m.!Eo
drop table tabname AX
Q.E$1g
6、说明:增加一个列 I*$-[3/
Alter table tabname add column col type b|;h$otC
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 NqveL<r`
7、说明:添加主键: Alter table tabname add primary key(col) {wgq>cb
说明:删除主键: Alter table tabname drop primary key(col) O1wo
KkfV
8、说明:创建索引:create [unique] index idxname on tabname(col....) TB= _r(:l+
删除索引:drop index idxname Y\+LBbB8
注:索引是不可更改的,想更改必须删除重新建。 UJ(UzKq8
9、说明:创建视图:create view viewname as select statement vp9wRGd
删除视图:drop view viewname E|jU8qz>P
10、说明:几个简单的基本的sql语句 l2YA/9.
选择:select * from table1 where 范围 g_A#WQyh\'
插入:insert into table1(field1,field2) values(value1,value2) 7%[ YX
删除:delete from table1 where 范围 e,Y<$kPV
更新:update table1 set field1=value1 where 范围 .}uri1k"@k
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Y9&na&vY?
排序:select * from table1 order by field1,field2 [desc] U0iV
E+)Bt
总数:select count as totalcount from table1 jw
5 U-zi
求和:select sum(field1) as sumvalue from table1 HLdHyK/S
平均:select avg(field1) as avgvalue from table1 X[f)0w%
最大:select max(field1) as maxvalue from table1 c-!3wvt)
最小:select min(field1) as minvalue from table1 2$`Y 4b 3t
zL3zvOhu}
`M. I.Z_
%<'.c9u5
11、说明:几个高级查询运算词 6eA)d#
FjLMN{eH/
Xr'b{&
A: UNION 运算符 E@#<p-@~
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 A)Rh
Bi
B: EXCEPT 运算符 nR w f;K
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 Aa]3jev
C: INTERSECT 运算符 N R4\TU
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 Aon.Y Z
注:使用运算词的几个查询结果行必须是一致的。 CS5[E-%}T=
12、说明:使用外连接 v(=0hY9
O
A、left outer join: g!o2vTt5
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 <G`1(,g
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c }' sW[?ik
B:right outer join: 6j+X@|2^
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 `e?~c'a@
C:full outer join: O:
#SjjK
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 wZW\r!Us
F?0Q AA
qZ
+K4H
二、提升 WK@<#
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) }TAG7U*
法一:select * into b from a where 1<>1 -_eG/o=M
法二:select top 0 * into b from a RCxwiZaf33
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) E H%hL5(
insert into b(a, b, c) select d,e,f from b; 5hDy62PRr
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) [1ClZ~f
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 TIR Is1
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. m~fDDQs
4、说明:子查询(表名1:a 表名2:b) pn){v
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) mEkYT
5、说明:显示文章、提交人和最后回复时间 {MTtj4$
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b (d
(>0YMv
6、说明:外连接查询(表名1:a 表名2:b) eT ]*c?"
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c =dQ/^C_hj
7、说明:在线视图查询(表名1:a ) 4\g[&
select * from (SELECT a,b,c FROM a) T where t.a > 1; ;DVg[#
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 z|Yt|W
select * from table1 where time between time1 and time2 Df:/r%
select a,b,c, from table1 where a not between 数值1 and 数值2 i1A<0W|
9、说明:in 的使用方法 vy2"B ch
select * from table1 where a [not] in ('值1','值2','值4','值6') fakad#O
10、说明:两张关联表,删除主表中已经在副表中没有的信息 uJeJ=7,EO
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) OdL/%Zp}
11、说明:四表联查问题: VeZd\Oe
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 ..... +c,
^KHW
12、说明:日程安排提前五分钟提醒 T:9M|mD
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 E*fa&G~s )
13、说明:一条sql 语句搞定数据库分页 Ap;^\5
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 n2Mpo\2
14、说明:前10条记录 pG"hZB3)
select top 10 * form table1 where 范围 AZA5>Y
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.) Q9B!0G.-bs
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) V0&7MY *
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 01uj-!D$@
(select a from tableA ) except (select a from tableB) except (select a from tableC) 'Ffvd{+:8
17、说明:随机取出10条数据 ~l{Qz0&
select top 10 * from tablename order by newid() W}}ZP];
18、说明:随机选择记录 ! hEZV&y
select newid() nZc6
*jiz
19、说明:删除重复记录 H~SU:B:
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) D ]
n|d+
20、说明:列出数据库里所有的表名 5p5"3m;M7
select name from sysobjects where type='U' apgKC;
21、说明:列出表里的所有的 -1`}|t;
select name from syscolumns where id=object_id('TableName') QnS#"hc\a
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 *M0O&" ~j
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type m({q<&]Qp
显示结果: q;IuV&B
type vender pcs C dPQhv)m
电脑 A 1 Q2* 8c$
电脑 A 1 pSIXv%1J
光盘 B 2 %L7DC`
光盘 A 2 SW+;%+`
手机 B 3 \Y!=O=za]
手机 C 3 N'$P(
bx
23、说明:初始化表table1 ~Fl\c-
TRUNCATE TABLE table1 D/%v/mpj$
24、说明:选择从10到15的记录 ~ _tK.m3
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc }J92TV
`T ^0&#
{4f%UnSz(
Qu7ML]e?z
三、技巧 es\
qnq
1、1=1,1=2的使用,在SQL语句组合时用的较多 jsr)
"where 1=1" 是表示选择全部 "where 1=2"全部不选, :`"-Jf
如: R!WDQGR(2
if @strWhere !='' h4MBw=Tz~
begin 0Js5 '
9}H
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere zb02\xvf
end &jQqlQ j
else @H(7Mt
begin QtWe,+WWV
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' #N64ZXz_
end gm8JxhL
我们可以直接写成 (nuTfmt>
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere SMRCG"3qwA
2、收缩数据库 /6yVbo"
--重建索引 b&1hj[`)
DBCC REINDEX "&^KnWk=
DBCC INDEXDEFRAG 7^UY%t
--收缩数据和日志 _v,Wl/YAp
DBCC SHRINKDB 3pL4Zhf
DBCC SHRINKFILE px+]/P<dX
3、压缩数据库 ,@f |t&
dbcc shrinkdatabase(dbname) W$J.B!O
4、转移数据库给新用户以已存在用户权限 h^`@%g9 S
exec sp_change_users_login 'update_one','newname','oldname' MBKF8b'k
go kApD D[ N
5、检查备份集 /Dt:4{aTOC
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ui|6ih$+
6、修复数据库 T?=]&9Y'
ALTER DATABASE [dvbbs] SET SINGLE_USER 9Av{>W?
GO b E40^e
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK In!^+j
GO GkU$Z @
ALTER DATABASE [dvbbs] SET MULTI_USER Zp6VH
GO eWD!/yr|
7、日志清除 l=S!cj;
SET NOCOUNT ON p} eO
DECLARE @LogicalFileName sysname, P*PJ
@MaxMinutes INT, CL-?Mi=Uc
@NewSize INT f4NN?"W)
USE tablename -- 要操作的数据库名 vS3Y9|-:
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 V$Oj@vI
@MaxMinutes = 10, -- Limit on time allowed to wrap log. R"CF xo
@NewSize = 1 -- 你想设定的日志文件的大小(M) `zl,|}u)
-- Setup / initialize BePb8
k<y
DECLARE @OriginalSize int ?@`5^7*
SELECT @OriginalSize = size $*P+
FROM sysfiles h4Arg~Or
WHERE name = @LogicalFileName lU&2K$`
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ]6|?H6'/`v
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + "SWL@}8vx
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ,nP nH1vb
FROM sysfiles 'xaEG,P
WHERE name = @LogicalFileName YZnFU( j
CREATE TABLE DummyTrans I|c?*~7*
(DummyColumn char (8000) not null) $-!7<a-
DECLARE @Counter INT, oblw!)
@StartTime DATETIME, K>XZrt
@TruncLog VARCHAR(255) J#iuF'%Ds
SELECT @StartTime = GETDATE(), EUH9R8)
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' w Bm4~~_
DBCC SHRINKFILE (@LogicalFileName, @NewSize) p}wysVB
EXEC (@TruncLog) Lk^bzW>f
-- Wrap the log if necessary. Tkp"mT
v?<
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 4mX]JH`UTe
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Txpj#JD
AND (@OriginalSize * 8 /1024) > @NewSize wGIRRM !b
BEGIN -- Outer loop. hg'eSU$J
SELECT @Counter = 0 6!*zgA5M'
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000))
z{V#_(
BEGIN -- update J\'f5)k
INSERT DummyTrans VALUES ('Fill Log') bS55/M w
DELETE DummyTrans ^U,C])n
SELECT @Counter = @Counter + 1 fmUrwI1 %
END ^r7KEeVD
EXEC (@TruncLog) .i` -t"
END L/vw7XNrX
SELECT 'Final Size of ' + db_name() + ' LOG is ' + N#R8ez`
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + GU Mf}y
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' _@y9=e
FROM sysfiles 9O^~l2`
WHERE name = @LogicalFileName G2@'S&2@s
DROP TABLE DummyTrans 9fM=5
SET NOCOUNT OFF fJ\u8
8、说明:更改某个表 q%/.+g2-\
exec sp_changeobjectowner 'tablename','dbo' ('d,Sh
9、存储更改全部表 #E<~WpP
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Cgf4E{\U!
@OldOwner as NVARCHAR(128), 1UB.2}/:
@NewOwner as NVARCHAR(128) B/hQvA;(
AS ?A*<Z%}1?
DECLARE @Name as NVARCHAR(128) LHA:frC
DECLARE @Owner as NVARCHAR(128) 5C*-v,hF
DECLARE @OwnerName as NVARCHAR(128) G- ]_
d
DECLARE curObject CURSOR FOR Cyg(~7]
select 'Name' = name, ozHL'H
'Owner' = user_name(uid) U56g|V
from sysobjects Eb29tq
where user_name(uid)=@OldOwner v6=X]Ji{YA
order by name k>!i
_lb
OPEN curObject pB%oFWqK
FETCH NEXT FROM curObject INTO @Name, @Owner ^HI2Vp
WHILE(@@FETCH_STATUS=0) zd F;!
BEGIN e-lc2$o7{
if @Owner=@OldOwner X .K*</(g
begin :inVwc
set @OwnerName = @OldOwner + '.' + rtrim(@Name) |^F$Ta
exec sp_changeobjectowner @OwnerName, @NewOwner [?2?7>D8
end u'Hh||La"
-- select @name,@NewOwner,@OldOwner X~\O]
FETCH NEXT FROM curObject INTO @Name, @Owner N1vA>(2A
END ^EmePkPI
close curObject 7v.O Lp
deallocate curObject evVxzU&
GO 8S[bt@v
10、SQL SERVER中直接循环写入数据 9c{ ~$zJW
declare @i int o{mVXidE
set @i=1 ^b= ;
while @i<30 lx?v
.:zl\
begin #}tdA(
-
insert into test (userid) values(@i) dWhqu68_
set @i=@i+1 #AO}JP
end 2G3Hi;q18
小记存储过程中经常用到的本周,本月,本年函数 ^R7X!tOq4
Dateadd(wk,datediff(wk,0,getdate()),-1) I:MrX
Dateadd(wk,datediff(wk,0,getdate()),6) uOd1:\%*
Dateadd(mm,datediff(mm,0,getdate()),0) 0+w(cf~6
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) a,fcR<
Dateadd(yy,datediff(yy,0,getdate()),0) eOZ~p
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 8N<mV^|}
上面的SQL代码只是一个时间段 $!\L6;:
Dateadd(wk,datediff(wk,0,getdate()),-1) n+vv
%
Dateadd(wk,datediff(wk,0,getdate()),6) 5fmQ+2AC1
就是表示本周时间段. 7.kH="@
下面的SQL的条件部分,就是查询时间段在本周范围内的: $8[JL\
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) C 8d9(u
而在存储过程中 PdRDUG{Jy
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) L,,*8
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) |0_5iFAB|