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。 h[PYP5{L
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一、基础 F$[ U|%*
1、说明:创建数据库 o`Ta("9^
CREATE DATABASE database-name rD*sl}
2、说明:删除数据库 y
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drop database dbname XP@1~$
3、说明:备份sql server
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--- 创建 备份数据的 device =9j8cC5y
USE master _)\c&.p]f
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' s>^dxF!+
--- 开始 备份 /Ml.}7&
BACKUP DATABASE pubs TO testBack v'e[GB0
4、说明:创建新表 ;X?mmv'
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) X,LD
根据已有的表创建新表: ` \+@Fwfx
A:create table tab_new like tab_old (使用旧表创建新表) ~V$|i"
B:create table tab_new as select col1,col2... from tab_old definition only p ZZc:\fJ
5、说明:删除新表 _r2J7&
drop table tabname 7^g&)P
6、说明:增加一个列 x:QgjK
Alter table tabname add column col type 2 aL)
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 mQY_`&Jq
7、说明:添加主键: Alter table tabname add primary key(col) e#E2>Bj;
说明:删除主键: Alter table tabname drop primary key(col) VqS#waNrx
8、说明:创建索引:create [unique] index idxname on tabname(col....) kcQ'$<Mz<
删除索引:drop index idxname FXs*vg`
注:索引是不可更改的,想更改必须删除重新建。 %?m$`9yU
9、说明:创建视图:create view viewname as select statement HQB(*
删除视图:drop view viewname 8H_l:Z [:i
10、说明:几个简单的基本的sql语句 &\Amn?Iq
选择:select * from table1 where 范围 8HP6+c%
插入:insert into table1(field1,field2) values(value1,value2) 6,9o>zT%H
删除:delete from table1 where 范围 Ybn`3
更新:update table1 set field1=value1 where 范围 N&M~0iw
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Yh>]-SCw
排序:select * from table1 order by field1,field2 [desc]
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总数:select count as totalcount from table1 `P9XqWr
求和:select sum(field1) as sumvalue from table1 P><o,s"v
平均:select avg(field1) as avgvalue from table1 +-G<c6 |
最大:select max(field1) as maxvalue from table1 wR^ RM(1
最小:select min(field1) as minvalue from table1 qkC/\![@
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11、说明:几个高级查询运算词 #b~JDO(
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A: UNION 运算符 Lliqj1&
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 N"3b{Qio
B: EXCEPT 运算符 B`
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EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 HB7;0yt`:
C: INTERSECT 运算符 X_7UJ
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INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 3}/&w\$
注:使用运算词的几个查询结果行必须是一致的。 D#o}cC.
12、说明:使用外连接 OD5m9XS
A、left outer join: DS'n
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 )4&cph';
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c -UD\;D?$
B:right outer join: oIefw:FE,a
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。 ;vIrGZV<
C:full outer join: u&n'
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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。 uh?>-
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二、提升 pbU!dOU~e
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Q*b]_0Rb
法一:select * into b from a where 1<>1 ,JEFGI{
法二:select top 0 * into b from a D)d~3`=#
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) >>5NX"{
insert into b(a, b, c) select d,e,f from b; WASU0
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) PoT`}-9
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 a(0*um(
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. pi
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4、说明:子查询(表名1:a 表名2:b) o5Q{/
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) fF V!)Zj
5、说明:显示文章、提交人和最后回复时间 OdB?_.+$
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b f4PIoZ e
6、说明:外连接查询(表名1:a 表名2:b) YxP@!U9dE,
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c <NuUW9+
7、说明:在线视图查询(表名1:a ) `YIf_a{
select * from (SELECT a,b,c FROM a) T where t.a > 1; Iwc{R8BV
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 48*Do}l]
select * from table1 where time between time1 and time2 u6bXv(
select a,b,c, from table1 where a not between 数值1 and 数值2 o!!yd8~*r
9、说明:in 的使用方法 A$a1(8H
select * from table1 where a [not] in ('值1','值2','值4','值6') n2fbp\ I
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Q
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) (owrdPT!
11、说明:四表联查问题:
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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 ..... `^4vT3e
12、说明:日程安排提前五分钟提醒 -Q
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 $n^gmhp
13、说明:一条sql 语句搞定数据库分页 lj?v4$
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 ]._LLSzWhg
14、说明:前10条记录 :.45u}[
select top 10 * form table1 where 范围 \
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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.) ~PHB_cyth
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) B!\;/Vk
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 }eRD|1
(select a from tableA ) except (select a from tableB) except (select a from tableC) 14"J d\M8
17、说明:随机取出10条数据 ](^(=%
select top 10 * from tablename order by newid() Ix(><#P
18、说明:随机选择记录 6O}`i>/6M
select newid() J|w)&bV
19、说明:删除重复记录 m:/wG&
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) MC{
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20、说明:列出数据库里所有的表名 44F`$.v96
select name from sysobjects where type='U' qvv2O1c"A
21、说明:列出表里的所有的 @`,1:
select name from syscolumns where id=object_id('TableName') -%I2[)F<
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 B0ndcB-
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type /0eYMG+K=
显示结果: izx#3u$P
type vender pcs 37RLE1Yf
电脑 A 1 A4]s~Ur
电脑 A 1 ]7/
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光盘 B 2 eVM/uDD
光盘 A 2 dF~8XYo
手机 B 3 [V)
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手机 C 3 u3o#{~E/#
23、说明:初始化表table1 `Ps:d^8*P
TRUNCATE TABLE table1 m,t|IgDh
24、说明:选择从10到15的记录 p+Y>F\r&w
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc <dvy"Dx
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三、技巧 +(+Itmx2&
1、1=1,1=2的使用,在SQL语句组合时用的较多 7H|$4;X^
"where 1=1" 是表示选择全部 "where 1=2"全部不选, d`(@_czdF
如: =lu/9
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if @strWhere !='' "5,
begin zdp/|"D!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 0]jA<vLR
end t2r?N}"P
else ~jb"5CX
begin ]J#9\4Sq
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' vC5n[0
end i}~SDY
我们可以直接写成 jH6&q~#
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere
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2、收缩数据库 m-jHze`D3
--重建索引 E~AjK'Z
DBCC REINDEX D91e\|]
DBCC INDEXDEFRAG 3q?\r`
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--收缩数据和日志 T]?n)L,2
DBCC SHRINKDB "hy.GWF|*
DBCC SHRINKFILE 0pSmj2/,.
3、压缩数据库 @GvztVYo
dbcc shrinkdatabase(dbname) 5j-]EJb
4、转移数据库给新用户以已存在用户权限 f u9Cx
exec sp_change_users_login 'update_one','newname','oldname' CQpCS_M
go YQS5P#
5、检查备份集 8dlw-Q'S
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' z-c}NdW
6、修复数据库 N72Yq)(
ALTER DATABASE [dvbbs] SET SINGLE_USER MG?0>^F
GO }E7:ihy
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ai0Ut
GO +nT'I!//
ALTER DATABASE [dvbbs] SET MULTI_USER R9!Uo
GO G!XIc>F*
7、日志清除 2m~V{mUT!
SET NOCOUNT ON zR32PG>9
DECLARE @LogicalFileName sysname, yu;SH[{Wi
@MaxMinutes INT, .&x}NYX4
@NewSize INT ]K*8O<
USE tablename -- 要操作的数据库名 sQ8s7l0D
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 h?$T!D>
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 3<=G?of
@NewSize = 1 -- 你想设定的日志文件的大小(M) /By)"
-- Setup / initialize M1%Dg'}G
DECLARE @OriginalSize int _A0mxq
SELECT @OriginalSize = size 0n/gd"M
FROM sysfiles UG<79"\i
WHERE name = @LogicalFileName ]@M5&
SELECT 'Original Size of ' + db_name() + ' LOG is ' + -uH#VP{0M
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 8x[YZ@iM-
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' $8crN$ye
FROM sysfiles 0=="^t_
WHERE name = @LogicalFileName \))=gu)I
CREATE TABLE DummyTrans vhb)2n
(DummyColumn char (8000) not null) x{&w?ng
DECLARE @Counter INT, 1HPx|nmE]
@StartTime DATETIME, leCVK.
@TruncLog VARCHAR(255) @;?T~^nGj
SELECT @StartTime = GETDATE(), PG]%Bv57
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Gx
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) -`Y:~q1
EXEC (@TruncLog) :>81BuMvg
-- Wrap the log if necessary. b,IocD6v;P
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired .{S8f#p9T
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) efY8M2
AND (@OriginalSize * 8 /1024) > @NewSize 1+7GUSIb
BEGIN -- Outer loop. ,2]X}&{i
SELECT @Counter = 0 O$ HBO
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) z7-k`(l4
BEGIN -- update @WKzX41'
INSERT DummyTrans VALUES ('Fill Log') 99EXo+g
DELETE DummyTrans [0UGuj
SELECT @Counter = @Counter + 1 eVl'\aUd
END J/6`oh?,Q
EXEC (@TruncLog) |D.O6?v@
END 178Mb\8
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 9RwawTM
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + !SKV!xH9
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ;;)`c/$
FROM sysfiles {>bW>RO)
WHERE name = @LogicalFileName ="d*E/##
DROP TABLE DummyTrans 5%}wV,Y
SET NOCOUNT OFF j:bgR8%e
8、说明:更改某个表 a1j.fA
exec sp_changeobjectowner 'tablename','dbo' _Zc%z@}
9、存储更改全部表 gf+d!c(/
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch iL7VFo:Q
@OldOwner as NVARCHAR(128), bOI3^T
@NewOwner as NVARCHAR(128) J/A[45OD
AS syzdd
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DECLARE @Name as NVARCHAR(128) 4"=Vq5
DECLARE @Owner as NVARCHAR(128) _3Cn{{ A0
DECLARE @OwnerName as NVARCHAR(128) U,Mx@KdV
DECLARE curObject CURSOR FOR D?M!ra
select 'Name' = name, xE-7P|2
'Owner' = user_name(uid) *XWq?hi
from sysobjects aTzDew
where user_name(uid)=@OldOwner -@&1`@):{
order by name 6/ `.(fL1
OPEN curObject 4eH.9t
FETCH NEXT FROM curObject INTO @Name, @Owner ai*b:Q
WHILE(@@FETCH_STATUS=0) Z"s|]K "
BEGIN _e!F~V.
if @Owner=@OldOwner i5F:r|
begin *xR
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) m%#`y\]I
exec sp_changeobjectowner @OwnerName, @NewOwner j'p1q
end +([!A6:
-- select @name,@NewOwner,@OldOwner yGpz,X4x
FETCH NEXT FROM curObject INTO @Name, @Owner y]e> E
END =xianQ<lK
close curObject t_ur&.^SB
deallocate curObject A`6ra}U<
GO )$Z(|M4
10、SQL SERVER中直接循环写入数据 P;]F=m+*V
declare @i int [hRU&z;W
set @i=1 :!zC"d9@
while @i<30 V,ZY*f0
begin m?[5J)eR
insert into test (userid) values(@i) H0"= Vs,n
set @i=@i+1 "gW7<ilw
end
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小记存储过程中经常用到的本周,本月,本年函数 D,ly#Nn
Dateadd(wk,datediff(wk,0,getdate()),-1) OVk~N)
Dateadd(wk,datediff(wk,0,getdate()),6) ->lu#;A5
Dateadd(mm,datediff(mm,0,getdate()),0) H
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) e1q"AOV 6
Dateadd(yy,datediff(yy,0,getdate()),0) O''y>N9
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 9TxyZL
上面的SQL代码只是一个时间段 W2wpcc
Dateadd(wk,datediff(wk,0,getdate()),-1) 4O{Avt7C
Dateadd(wk,datediff(wk,0,getdate()),6) nkeI60
就是表示本周时间段. B
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下面的SQL的条件部分,就是查询时间段在本周范围内的: cyd~2\Kv~
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) !~-6wN"k
而在存储过程中 +7}iu/B!9
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) /OGA$eP
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 9x`4RE