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。 -AD`(b7q
^W%F?#ELN2
RrCG(Bh
一、基础 SFtcO
1、说明:创建数据库 MZf?48"f
CREATE DATABASE database-name O43"-
2、说明:删除数据库 ')yYpWO
drop database dbname 2Og5e
3、说明:备份sql server dMsS OP0E
--- 创建 备份数据的 device y4|<+9<7
USE master YT'V/8US
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 4:Ju|g]O
--- 开始 备份 Yy]TU} PY
BACKUP DATABASE pubs TO testBack WHOy\j},V
4、说明:创建新表 i%<NKE;v7m
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 0QPY+6
根据已有的表创建新表:
`+vQ5l$;L
A:create table tab_new like tab_old (使用旧表创建新表) *,:2O&P
B:create table tab_new as select col1,col2... from tab_old definition only RFFbS{U*
5、说明:删除新表 5[B)U">]
drop table tabname ,YBO}l
6、说明:增加一个列 ,ZrR*W?iF
Alter table tabname add column col type 8EdaqF
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 [bX^_ Y
7、说明:添加主键: Alter table tabname add primary key(col) dyf>T}Iy
说明:删除主键: Alter table tabname drop primary key(col) FW;}S9u3
8、说明:创建索引:create [unique] index idxname on tabname(col....) -:'%YHxX
删除索引:drop index idxname NT5##XOB
注:索引是不可更改的,想更改必须删除重新建。 6)Za K
9、说明:创建视图:create view viewname as select statement 3dbaCusT$
删除视图:drop view viewname
: *[mvF
10、说明:几个简单的基本的sql语句 4
$Kzh
选择:select * from table1 where 范围 +_*NY~
插入:insert into table1(field1,field2) values(value1,value2) ]3='TN8aQF
删除:delete from table1 where 范围 "x$L2>9
更新:update table1 set field1=value1 where 范围 M[O22wFs
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! g{sp<w0
排序:select * from table1 order by field1,field2 [desc] {:_*P
TVk
总数:select count as totalcount from table1 ,?qJAV~>
求和:select sum(field1) as sumvalue from table1 c V@^<
平均:select avg(field1) as avgvalue from table1 TNN@G~@cm
最大:select max(field1) as maxvalue from table1 %uV,p!| )
最小:select min(field1) as minvalue from table1 ZBx,'ph}4
'~f*O0_
qBK68B)
vRW;{,d
11、说明:几个高级查询运算词
(6mw@gzr
c2:,
>c
Tt2v
A: UNION 运算符 +lFBH(o]X
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。 /u90)x
B: EXCEPT 运算符 tBZ?UAe;
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。 {&D$U'ye
C: INTERSECT 运算符 ,\3Cq2h
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 <6hs<qXqi
注:使用运算词的几个查询结果行必须是一致的。 aL;zN%Tw
12、说明:使用外连接 "7Kw]8mRR
A、left outer join: D,FgX/&i/
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ;"EDFH#W
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c "W4|}plnu
B:right outer join: u6Ux nqNc
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 H|j]uLZ
C:full outer join: glM42s
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 <~v4BiQ3l^
i88`W&tI{
=Ov,7<8o
二、提升 |na9I6
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) U Lq`!1{
法一:select * into b from a where 1<>1 NL-PQ%lUA
法二:select top 0 * into b from a J &=5h.G$
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) D?*du#6
insert into b(a, b, c) select d,e,f from b; sH1ucZ>9Y
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) VTDnh*\5
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 3?h!nVI+2J
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. g3%x"SlIU
4、说明:子查询(表名1:a 表名2:b) TI"Ki$jC
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) {LqYb:/C5U
5、说明:显示文章、提交人和最后回复时间 tId,Q>zH
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b lq`7$7-4
6、说明:外连接查询(表名1:a 表名2:b) @V Tw>=94
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Vz!{nL0Q(
7、说明:在线视图查询(表名1:a ) "~6&rt
select * from (SELECT a,b,c FROM a) T where t.a > 1; gr.G']9lNq
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 sMJa4P>O@
select * from table1 where time between time1 and time2 #%OS=.V
select a,b,c, from table1 where a not between 数值1 and 数值2 v!<FeLW
9、说明:in 的使用方法 -{d(~XIo
select * from table1 where a [not] in ('值1','值2','值4','值6') f1o^:}5x
10、说明:两张关联表,删除主表中已经在副表中没有的信息 SjJ$Oinc
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) *(i%\
11、说明:四表联查问题: r<P? F
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 ..... &js$qgY
12、说明:日程安排提前五分钟提醒 |6Iw\YU
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 G2c\"[N1/
13、说明:一条sql 语句搞定数据库分页 L-q)48+^k
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 hA&m G33
14、说明:前10条记录 %){/O}I]>
select top 10 * form table1 where 范围 -,mV~y
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) [,~;n@jz
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) J]48th0,
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 t0:~BYXu
(select a from tableA ) except (select a from tableB) except (select a from tableC) L/bvM?B^
17、说明:随机取出10条数据 Z%3)w.
select top 10 * from tablename order by newid() NJoHrhC='
18、说明:随机选择记录 * "?,.
select newid() |
ObA=[j
19、说明:删除重复记录 8zJye6f;l
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) MfFmJ7>Bg
20、说明:列出数据库里所有的表名 1O)m(0tb[
select name from sysobjects where type='U' 7(LB}
21、说明:列出表里的所有的 !|ic{1!_
select name from syscolumns where id=object_id('TableName') 5Go@1X]I
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 B&*`A&^y
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type SEZ08:>x r
显示结果: r>"l:GZ
type vender pcs .0X 5Vy
电脑 A 1 ~1,$
电脑 A 1 = P$7
"
光盘 B 2 0\"]XYOH
光盘 A 2 <
r b5'
手机 B 3 +tYskx/
手机 C 3 "oR%0pU*
23、说明:初始化表table1 YsTF10
TRUNCATE TABLE table1 Ac
+fL
24、说明:选择从10到15的记录 QNj6ETB-d
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc sN1I+X
kCoEdQ_
_XI,z0(
2&o3OKt
三、技巧 jgYe\dinM
1、1=1,1=2的使用,在SQL语句组合时用的较多 YB]^Y^" e
"where 1=1" 是表示选择全部 "where 1=2"全部不选, {qS Ye!`
如: {qH+S/
if @strWhere !='' k)9
pkPl
begin T^X um2Ec
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere o1&Oug
end c&SSf_0O*
else Y#U0g|UDn
begin g9=O<u#
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 7Uh/Gl
end N\hHu6
我们可以直接写成 h>|IA@;|f
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere P>*`<$FR
2、收缩数据库 `DP4u\6_
--重建索引 {E1^Wn1M
DBCC REINDEX Hegj_FQ
DBCC INDEXDEFRAG h~&5;
--收缩数据和日志 DwXSlsN3v
DBCC SHRINKDB (xBWxeL~
DBCC SHRINKFILE k]A$?C0Q<%
3、压缩数据库 {r?Ly1 5
dbcc shrinkdatabase(dbname) M_;hfpJZ
4、转移数据库给新用户以已存在用户权限 N#X(gEV
exec sp_change_users_login 'update_one','newname','oldname' >>h0(G|
go XO/JnJ^B
5、检查备份集 gvxOo#8]
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' QUc&f+~
6、修复数据库 nN[QUg
ALTER DATABASE [dvbbs] SET SINGLE_USER _w9:([_
GO }_?FmuU
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK gBXbB9
GO Gii1|pLZ1
ALTER DATABASE [dvbbs] SET MULTI_USER r5!Sps3B
GO w"E.Va
7、日志清除 ?)/&tk9.n
SET NOCOUNT ON \ 3l3,VYH
DECLARE @LogicalFileName sysname, <\\,L@
@MaxMinutes INT, yd`f<Hr<m
@NewSize INT *U|2u+| F
USE tablename -- 要操作的数据库名 <%LN3T
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 I h 19&D
@MaxMinutes = 10, -- Limit on time allowed to wrap log. "nn>I}jK
@NewSize = 1 -- 你想设定的日志文件的大小(M) hr GfA
-- Setup / initialize J|WkPv2
DECLARE @OriginalSize int 9,AHC2kn%
SELECT @OriginalSize = size 8lT2qqlr
FROM sysfiles *W1:AGpz
WHERE name = @LogicalFileName e5m-7{h@
SELECT 'Original Size of ' + db_name() + ' LOG is ' + PZCOJK
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 2?9gf,U
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' !
d " i
FROM sysfiles P%kJq^&
WHERE name = @LogicalFileName (>gHfC>(lq
CREATE TABLE DummyTrans @ u2P&|:{
(DummyColumn char (8000) not null) >l0D,-O]m
DECLARE @Counter INT, DzK%$#{<
@StartTime DATETIME, /AUXO]
@TruncLog VARCHAR(255) !"
7ip9a
SELECT @StartTime = GETDATE(), (n~GKcA
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' %0^taA
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ;{Su:Ixg
EXEC (@TruncLog) D TSK*a `
-- Wrap the log if necessary. +Zo&c}
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired P{h$> 6c
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) o jy[<
AND (@OriginalSize * 8 /1024) > @NewSize _6&TCd<
BEGIN -- Outer loop. c27\S?\
Jd
SELECT @Counter = 0 @m(ja@YC
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) I'T@}{h
BEGIN -- update q.g0Oz@z
INSERT DummyTrans VALUES ('Fill Log') Umt?COc
DELETE DummyTrans '6W|,
SELECT @Counter = @Counter + 1 XCU>b[Cj,
END >$iQDVh!
EXEC (@TruncLog) !Won<:.[0
END h(wu5G0C#u
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Wk&g!FR
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + h oL"K
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' L]|[AyNu
FROM sysfiles mtg3}etA
WHERE name = @LogicalFileName ,Z6\%:/
DROP TABLE DummyTrans HOrD20
SET NOCOUNT OFF [qGj*`@C
8、说明:更改某个表 bB`p-1
exec sp_changeobjectowner 'tablename','dbo' xxC2F:Q?U
9、存储更改全部表 ag\xwS#i5H
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch A ^wIsAxT
@OldOwner as NVARCHAR(128), zw,=mpf3_
@NewOwner as NVARCHAR(128) @z1Yj"^Pm
AS w-M,@[G
DECLARE @Name as NVARCHAR(128) 1'{A,!
DECLARE @Owner as NVARCHAR(128) lYt|C^
DECLARE @OwnerName as NVARCHAR(128) JVgV,4 1
DECLARE curObject CURSOR FOR P7`sJ("#
select 'Name' = name, |Q)c{9sD
'Owner' = user_name(uid) b/eJEL
from sysobjects )FnJLd
where user_name(uid)=@OldOwner r#CQCq
order by name CHPu$eu
OPEN curObject Lupug"p0
FETCH NEXT FROM curObject INTO @Name, @Owner 9e*v&A2Y'
WHILE(@@FETCH_STATUS=0) Ckc4U. t|
BEGIN :n} NQzs
if @Owner=@OldOwner -
P$mN6h
begin "}(g3Iy
set @OwnerName = @OldOwner + '.' + rtrim(@Name) $ 3/G)/A
exec sp_changeobjectowner @OwnerName, @NewOwner Z* Fxr;)d
end '*6S0zt
-- select @name,@NewOwner,@OldOwner !C$bOhc
FETCH NEXT FROM curObject INTO @Name, @Owner @d]a#ypU
END >w~Hq9
close curObject nA#FGfZ{Ge
deallocate curObject *$eMM*4
GO sD[G?X
10、SQL SERVER中直接循环写入数据 Fuuy_+p@G
declare @i int W"a% IO%'
set @i=1 3+j!{tJ
z2
while @i<30 a$r<%a6
begin L(bYG0ZI5C
insert into test (userid) values(@i) (`
N@4w=
set @i=@i+1 XpH]CF
end =I}8-AS~V
小记存储过程中经常用到的本周,本月,本年函数 Bi'qy]%
Dateadd(wk,datediff(wk,0,getdate()),-1) uGxh}'&
Dateadd(wk,datediff(wk,0,getdate()),6) gh{Z=_
Dateadd(mm,datediff(mm,0,getdate()),0) */ ~_ 3
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) vCB0x:/
Dateadd(yy,datediff(yy,0,getdate()),0) @6N$!Q?
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ?pF7g$>q
上面的SQL代码只是一个时间段 .(7end<
Dateadd(wk,datediff(wk,0,getdate()),-1) ?7Y6: zo$^
Dateadd(wk,datediff(wk,0,getdate()),6) YFF\m{#
就是表示本周时间段. O"D0+BK79e
下面的SQL的条件部分,就是查询时间段在本周范围内的: #@#/M)
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) EqV]/0-\
而在存储过程中 v7ShXX:
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) OcBKn=8
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) |H LU5=Y