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。 lO! Yl:;m%
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一、基础 f^b.~jXSR}
1、说明:创建数据库 _]@
CREATE DATABASE database-name NKd}g
2、说明:删除数据库 I !=ew |
drop database dbname '/%]B@!
3、说明:备份sql server zgXg-cr
--- 创建 备份数据的 device (`\ DDJ[
USE master 'hN_H}U
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' mN?y\GB
--- 开始 备份 N"1o>
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BACKUP DATABASE pubs TO testBack 6e0tA ()F
4、说明:创建新表 y_boJ
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Jw3VWc
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根据已有的表创建新表: UKV0xl
A:create table tab_new like tab_old (使用旧表创建新表) YEH /22
B:create table tab_new as select col1,col2... from tab_old definition only Z:9xf:g*
5、说明:删除新表 o{7wPwQ;*
drop table tabname
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6、说明:增加一个列 Y S/x;
Alter table tabname add column col type jD1/`g%
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。 .\XFhOsa
7、说明:添加主键: Alter table tabname add primary key(col) ^3"~
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说明:删除主键: Alter table tabname drop primary key(col) /k8Lu+OJ
8、说明:创建索引:create [unique] index idxname on tabname(col....) Wu3or"lcw*
删除索引:drop index idxname g<pr(7jO
注:索引是不可更改的,想更改必须删除重新建。 $p:RnH\H1
9、说明:创建视图:create view viewname as select statement vy&'A$ H
删除视图:drop view viewname sG{f xha
10、说明:几个简单的基本的sql语句
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选择:select * from table1 where 范围 SO @d\H
插入:insert into table1(field1,field2) values(value1,value2) 4eH:eCZze
删除:delete from table1 where 范围 @h7)M:l
更新:update table1 set field1=value1 where 范围 P/i{_r
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! hOZ:r =%
排序:select * from table1 order by field1,field2 [desc] >-U'mkIH
总数:select count as totalcount from table1 3L}eFg,d
求和:select sum(field1) as sumvalue from table1 3-x ;_
平均:select avg(field1) as avgvalue from table1 *\Z9=8yK
最大:select max(field1) as maxvalue from table1 9U~fc U6
最小:select min(field1) as minvalue from table1 U )kl!
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11、说明:几个高级查询运算词 Qw>~]d,Z
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A: UNION 运算符 o%3i(H
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。 >7g #e,d
B: EXCEPT 运算符 y5/frJ
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。 6mp8v`b
C: INTERSECT 运算符 #+CH0Z
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。 Wh).%K(t
注:使用运算词的几个查询结果行必须是一致的。 s&v7<)*q
12、说明:使用外连接 KU$:p^0l;*
A、left outer join: uoJ@Jt'j
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。 de7
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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 ;wGoEN
B:right outer join: 6%yt"XmT
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。 xER-TT#S
C:full outer join: |"]#jx*8KC
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。 5&)T[Q X`
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二、提升 L%S(z)xX3
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ^^
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法一:select * into b from a where 1<>1 2P35#QI[)
法二:select top 0 * into b from a |L9p. q
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用)
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insert into b(a, b, c) select d,e,f from b; jk(tw-B
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) ?+)>JvWDz
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 r+TvC{
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. aH/8&.JLi
4、说明:子查询(表名1:a 表名2:b) ;Mw<{X-
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) Ms<v81z5T
5、说明:显示文章、提交人和最后回复时间 J:Mn5hdK=
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ._%8H
6、说明:外连接查询(表名1:a 表名2:b) n4XEyCrD
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c u@]rR&h`
7、说明:在线视图查询(表名1:a ) b=@H5XTZyK
select * from (SELECT a,b,c FROM a) T where t.a > 1; w{8O$4
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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 ,#Pp_f<
select * from table1 where time between time1 and time2 )7c/i+FsC
select a,b,c, from table1 where a not between 数值1 and 数值2 2CMWJi
9、说明:in 的使用方法 `.i #3P
select * from table1 where a [not] in ('值1','值2','值4','值6') (N"9C+S}
10、说明:两张关联表,删除主表中已经在副表中没有的信息 953GmNZ7
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) vzX%x ul
11、说明:四表联查问题: &s#O iF8
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 ..... mUan(iJ
12、说明:日程安排提前五分钟提醒 SA{noM
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 :|\[a0ZL
13、说明:一条sql 语句搞定数据库分页 Cl6P,C
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 q}PUwN6
14、说明:前10条记录 mX/'Fta
select top 10 * form table1 where 范围 0g8ykGyx
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.) C5,\DdCX,
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ,NAwSmocVP
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 xWK0p'E0
(select a from tableA ) except (select a from tableB) except (select a from tableC) KzZfpdI92
17、说明:随机取出10条数据 ilRPV'S^
select top 10 * from tablename order by newid() x)R1aq
18、说明:随机选择记录 y(<+=
select newid() '}l7=r
19、说明:删除重复记录 {K N7Y"AI
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) q#6|/R*
20、说明:列出数据库里所有的表名 ffW-R)U|3
select name from sysobjects where type='U' l&|Tb8_'
21、说明:列出表里的所有的 g
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select name from syscolumns where id=object_id('TableName') lb{X 6_.
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。 !c"EgP+
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 uS<og P
显示结果: qWU59:d^{
type vender pcs y@h
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电脑 A 1 lT?Vt`==~M
电脑 A 1 XE'3p6
光盘 B 2 (%j V[Q
光盘 A 2 3qQ}U}-; |
手机 B 3 _RNP_$a
手机 C 3 =qvn?I^/
23、说明:初始化表table1 <S^Hy&MD>
TRUNCATE TABLE table1 zr ~4@JTS
24、说明:选择从10到15的记录 '/s/o]'sUd
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc }0Q
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三、技巧 ?7#{#sj
1、1=1,1=2的使用,在SQL语句组合时用的较多 a|5<L
"where 1=1" 是表示选择全部 "where 1=2"全部不选, O]XgA0]
如: T|&u?
if @strWhere !='' ^V~^[Yp
begin R5i xG9
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere d};[^q6X
end 9ec>#Vxx
else )gx*;z@
begin t*`G@Nj
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Z,-J
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end UGxF}Q
我们可以直接写成 x*!*2{
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ai<K6)
2、收缩数据库 e6>[Z C
--重建索引 y1h3Ch>Y
DBCC REINDEX DW>O]\I
DBCC INDEXDEFRAG hWiHKR]
--收缩数据和日志 9!PM1<p
DBCC SHRINKDB I^)_rOgM
DBCC SHRINKFILE Rzyaicj^c
3、压缩数据库 bZ#KfR
dbcc shrinkdatabase(dbname) th{ie2$
4、转移数据库给新用户以已存在用户权限 E9 w"?_A)
exec sp_change_users_login 'update_one','newname','oldname' WOeG3jMz?
go (Z0.H3
5、检查备份集 Vp1 Q^`a{G
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 8lyNg w1
6、修复数据库 FzOlM-)m
ALTER DATABASE [dvbbs] SET SINGLE_USER {z9,CwJan?
GO I* PxQ
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Uw?25+[b
GO 7:zoF],s
ALTER DATABASE [dvbbs] SET MULTI_USER &p+2Vz{
GO iOk`_LG#
7、日志清除 4QE")Ge
SET NOCOUNT ON hXD`OlX
DECLARE @LogicalFileName sysname, xouBBb=
@MaxMinutes INT, b)>l7nOc
@NewSize INT t R.>d
USE tablename -- 要操作的数据库名 "u'dd3!
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 -M+o;
@MaxMinutes = 10, -- Limit on time allowed to wrap log. /IG3>|R
@NewSize = 1 -- 你想设定的日志文件的大小(M) 1]W8A.ZS
-- Setup / initialize f7a"}.D$
DECLARE @OriginalSize int [U$`nnp
SELECT @OriginalSize = size ^U^K\rq 1u
FROM sysfiles 3*F|`js"
WHERE name = @LogicalFileName Q>xp 90&.n
SELECT 'Original Size of ' + db_name() + ' LOG is ' + f*EDSJu\
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 9%dO"t$-q
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' {qm5H7sL
FROM sysfiles -%Jm-^F I
WHERE name = @LogicalFileName 5! ]T%.rM
CREATE TABLE DummyTrans S] 4RGWn
(DummyColumn char (8000) not null) r!^VCA
DECLARE @Counter INT, ?'>[nm
@StartTime DATETIME, ti<;>P[4
@TruncLog VARCHAR(255) AHT(Z~C
SELECT @StartTime = GETDATE(), fc<,kRp
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' #bb$Icmtk
DBCC SHRINKFILE (@LogicalFileName, @NewSize) rW)}$|-Z
EXEC (@TruncLog) w[uwhd
-- Wrap the log if necessary. uZP(-}
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Qqd +=mgc
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) /GA-1cS_(
AND (@OriginalSize * 8 /1024) > @NewSize 5r0Sl89J
BEGIN -- Outer loop. "2}n(8
SELECT @Counter = 0 Q@s G6iz
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) {\VmNnw
BEGIN -- update /AIFgsaY
INSERT DummyTrans VALUES ('Fill Log') ?U,Xy xN
DELETE DummyTrans yn2k!2]&T<
SELECT @Counter = @Counter + 1 m~@Lt~LZs
END tbB.n
EXEC (@TruncLog) YCBUc<)
END v){X&HbP
SELECT 'Final Size of ' + db_name() + ' LOG is ' + r2&/Ii+
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + RRtOBrIedI
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' zB"y^g
FROM sysfiles 3P*"$ fH
WHERE name = @LogicalFileName Zf?jnDA
DROP TABLE DummyTrans '1lz`CAB+
SET NOCOUNT OFF /pp;3JPf
8、说明:更改某个表 R;w1& Z
exec sp_changeobjectowner 'tablename','dbo' s="cg0PD
9、存储更改全部表 ^.[+)0I
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch oTeQY[%$
@OldOwner as NVARCHAR(128), WhL"-f
@NewOwner as NVARCHAR(128) Tt{ft?H71
AS +H_ /
DECLARE @Name as NVARCHAR(128) 3H5<w4yk
DECLARE @Owner as NVARCHAR(128) 7':<I-Fm
DECLARE @OwnerName as NVARCHAR(128) <*opVy^
DECLARE curObject CURSOR FOR } d7o-
select 'Name' = name, 2yV{y#\
'Owner' = user_name(uid) ra]\!;}L0
from sysobjects UQ2;Dg G%
where user_name(uid)=@OldOwner mW."lzIl
order by name #~6X9,x=
OPEN curObject HmpV;
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FETCH NEXT FROM curObject INTO @Name, @Owner wHErF
#xo
WHILE(@@FETCH_STATUS=0) z6OJT6<'
BEGIN !Mk]%
if @Owner=@OldOwner peU1
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begin l 4cTN
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) ={nuz-3
exec sp_changeobjectowner @OwnerName, @NewOwner -:V2Dsr6;
end (<yQA. M
-- select @name,@NewOwner,@OldOwner o &E2ds3
FETCH NEXT FROM curObject INTO @Name, @Owner CHM+@lD
END %[m%QP1;p
close curObject ePI)~
deallocate curObject jhE3@c@pT
GO Q#I?nBin
10、SQL SERVER中直接循环写入数据 Y.o-e)zX
declare @i int ptpu
u=3"
set @i=1 SG3qNM: g
while @i<30 uX,ln(9I*H
begin @,TCg1@QJ
insert into test (userid) values(@i) btB> -pT
set @i=@i+1 #]Q.B\\
end K-7i4
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小记存储过程中经常用到的本周,本月,本年函数 =A^VzIj(
Dateadd(wk,datediff(wk,0,getdate()),-1) { FM:\/
Dateadd(wk,datediff(wk,0,getdate()),6) 8KS9!*.iZ
Dateadd(mm,datediff(mm,0,getdate()),0) ]m""ga
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) @33-UP9o
Dateadd(yy,datediff(yy,0,getdate()),0) PciiDh~/
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ON$-g_s>)
上面的SQL代码只是一个时间段 Z65]|
Dateadd(wk,datediff(wk,0,getdate()),-1) O0>^?dsL
Dateadd(wk,datediff(wk,0,getdate()),6) _ 6'HBE
就是表示本周时间段. 2a:JtJLl
下面的SQL的条件部分,就是查询时间段在本周范围内的: CFx$r_!~
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) :WdiH)Zv
而在存储过程中 W_G'wU3R
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) MXuiQ;./
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ESv&x6H