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。 g*]Gc%
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一、基础 C8 [W
1、说明:创建数据库 }&|S8:
CREATE DATABASE database-name x
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2、说明:删除数据库 x`:zC#
drop database dbname Y)="of
3、说明:备份sql server &)Y26*(`
--- 创建 备份数据的 device rZ}y'A
USE master ';<gc5EK
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' rfj>/?8!@
--- 开始 备份 cbsU!8
BACKUP DATABASE pubs TO testBack `x%(
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4、说明:创建新表 L<8:1/d\
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 8)n799<.
根据已有的表创建新表: 0V:7pSC{P
A:create table tab_new like tab_old (使用旧表创建新表) zl~`>
B:create table tab_new as select col1,col2... from tab_old definition only k4WUfL d
5、说明:删除新表 ,D#ssxV
drop table tabname :mOHR&2xR%
6、说明:增加一个列 FwD"Pc2
Alter table tabname add column col type T.m*LM
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。 gKyYBr
7、说明:添加主键: Alter table tabname add primary key(col)
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说明:删除主键: Alter table tabname drop primary key(col) ue?e}hF
8、说明:创建索引:create [unique] index idxname on tabname(col....) cPQUR^!5
删除索引:drop index idxname 2|Of$oMc
注:索引是不可更改的,想更改必须删除重新建。 @JFfyQ {-
9、说明:创建视图:create view viewname as select statement 1$1s0yg
删除视图:drop view viewname jV:Krk6T<
10、说明:几个简单的基本的sql语句 rK^Sn7 U
选择:select * from table1 where 范围 %OS}BAh^i
插入:insert into table1(field1,field2) values(value1,value2) c& &^Do
删除:delete from table1 where 范围 O+ ].'
更新:update table1 set field1=value1 where 范围 Yfro^}f
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Na6z1&wS
排序:select * from table1 order by field1,field2 [desc] 6Ja} N
总数:select count as totalcount from table1 W ='c+3O6
求和:select sum(field1) as sumvalue from table1 }V@ *
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平均:select avg(field1) as avgvalue from table1 kH&KE5
最大:select max(field1) as maxvalue from table1 |ATz<"q>
最小:select min(field1) as minvalue from table1 u;-_%?
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11、说明:几个高级查询运算词 wOfx7D
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A: UNION 运算符 rUg<(/c
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 v$H=~m
B: EXCEPT 运算符 >gQJ6q
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。 /&PRw<}>_o
C: INTERSECT 运算符 xbZx&`(
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。 c,wYXnJ_t
注:使用运算词的几个查询结果行必须是一致的。 C 2$_Ad=s
12、说明:使用外连接 j=&]=0F
A、left outer join: ~ 9F
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左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 wNNInS6
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c WAd5,RZ?
B:right outer join: UG@9X/l}
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 >v
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C:full outer join: lfle7;
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 H%`$@U>
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二、提升 @y"/hh_?
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) H<Ne\zAv
法一:select * into b from a where 1<>1 [2WJ];FJ
法二:select top 0 * into b from a [i"6\p&
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 8Uv2p{ <#
insert into b(a, b, c) select d,e,f from b; G)(vd0X1
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) 0@O:C::
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ][gr(-6 8
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. :NHP,"
4、说明:子查询(表名1:a 表名2:b) 6}(;~/L
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) 5c8tH=
5、说明:显示文章、提交人和最后回复时间 a/@F?\A
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b X-lB1uq^
6、说明:外连接查询(表名1:a 表名2:b) [Dzd39aKr
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c
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7、说明:在线视图查询(表名1:a ) K@RE-K6{
select * from (SELECT a,b,c FROM a) T where t.a > 1; ?QJS6i'k
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 @k|V4
select * from table1 where time between time1 and time2 Rhfx
select a,b,c, from table1 where a not between 数值1 and 数值2 <~d3L4h*<
9、说明:in 的使用方法 .eNeqC
select * from table1 where a [not] in ('值1','值2','值4','值6') t9U-c5bR
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?=I,2bP
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) l?f%2:}m
11、说明:四表联查问题: s%6{X48vY^
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 ..... 6d# 7
12、说明:日程安排提前五分钟提醒 9"g!J|+
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 e>6NO
13、说明:一条sql 语句搞定数据库分页 Ifx
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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 7o99@K,
14、说明:前10条记录 w3<%wN>tE
select top 10 * form table1 where 范围 Qm(KvL5
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.) ]ChGi[B~9
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) D#.N)@\
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 (m~gG|n4
(select a from tableA ) except (select a from tableB) except (select a from tableC) lTR/o
17、说明:随机取出10条数据 crDm2oA~t
select top 10 * from tablename order by newid() c}-WK*v
18、说明:随机选择记录 aAi"
select newid() `mt x+C
19、说明:删除重复记录 K(:
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) <N~&Leh
20、说明:列出数据库里所有的表名 > &V Y
select name from sysobjects where type='U' 9w:F_gr
21、说明:列出表里的所有的 \F; S
select name from syscolumns where id=object_id('TableName') N E/ _
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。 jE#&u DfI
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 GV"X) tGo
显示结果: &F 3'tf?
type vender pcs wBJP8wES=
电脑 A 1 Y+ Qm.
电脑 A 1 +\ZaVi
光盘 B 2 LP{@r ic
光盘 A 2 B*-A erdH
手机 B 3 xULcS :Q
手机 C 3 aj|gt
23、说明:初始化表table1 |'SgGg=E
TRUNCATE TABLE table1 c`M
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24、说明:选择从10到15的记录 :9.QhY)D
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc kKHGcm^r
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三、技巧 U8]BhJr$Q
1、1=1,1=2的使用,在SQL语句组合时用的较多 :dML+R#Ymh
"where 1=1" 是表示选择全部 "where 1=2"全部不选, R]xXG0
如: -udKGrT+
if @strWhere !='' vUD>+*D
begin xU(yc}vw,
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere NNTUl$
end |Ev VS
else E!6 Nf[
begin .8~zgpK
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' e"u89acp
end i4g99Kvl
我们可以直接写成 Dxx`<=&g
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere cpJ(77e
2、收缩数据库 zjlo3=FQX[
--重建索引
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DBCC REINDEX =L F9im
DBCC INDEXDEFRAG 1cvH
--收缩数据和日志 _rIFwT1]
DBCC SHRINKDB E#^?M#C
DBCC SHRINKFILE j%TcW!D-_
3、压缩数据库 7TaHE
dbcc shrinkdatabase(dbname) _N2tf/C&=
4、转移数据库给新用户以已存在用户权限 kM o7mkV
exec sp_change_users_login 'update_one','newname','oldname' @`S8d%6P
go )m4O7'2G
5、检查备份集 +1(L5Do}
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ?T\_"G
6、修复数据库 +^tw@b
ALTER DATABASE [dvbbs] SET SINGLE_USER !^*-]p/z
GO zSM;N^X 8?
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK E2xcd#ZD
GO `xm4?6
ALTER DATABASE [dvbbs] SET MULTI_USER se, 0Rvkt
GO Lr ;PESV
7、日志清除 JAA{5@ST
SET NOCOUNT ON QZ:xG:qyk;
DECLARE @LogicalFileName sysname, %J%ZoptY:
@MaxMinutes INT, Ohe*m[
@NewSize INT $4Ko
USE tablename -- 要操作的数据库名 Mq[|w2.
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 `*to(
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. UC{Tm f
@NewSize = 1 -- 你想设定的日志文件的大小(M) ulzQ[?OMl
-- Setup / initialize ~3F\7%Iqc
DECLARE @OriginalSize int 8 ta`sNy9
SELECT @OriginalSize = size 0*-nVC1
FROM sysfiles $k=5nJ
WHERE name = @LogicalFileName tUR9ti
SELECT 'Original Size of ' + db_name() + ' LOG is ' + e_{!8u.+
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + j^&{5s
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 2-#:Y
FROM sysfiles HGJfj*JH
WHERE name = @LogicalFileName Er]lObfQo
CREATE TABLE DummyTrans =O?#>3A}
(DummyColumn char (8000) not null) 'dFhZ08u}
DECLARE @Counter INT, vs|_l!n3
@StartTime DATETIME, fvUD'sx
@TruncLog VARCHAR(255) $F,&7{^
SELECT @StartTime = GETDATE(), *[MK{m
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' >tFv&1iR
DBCC SHRINKFILE (@LogicalFileName, @NewSize) buv*qPO
EXEC (@TruncLog) 9^5D28y
-- Wrap the log if necessary. `T \"B%
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 8iDg2_l`G
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) v1E=P7}\{s
AND (@OriginalSize * 8 /1024) > @NewSize AvNU\$B4aG
BEGIN -- Outer loop. !^/Mn
SELECT @Counter = 0 k5=VH5{S
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 8!c#XMHV
BEGIN -- update e yLVu.
INSERT DummyTrans VALUES ('Fill Log') '\iWp?`$
DELETE DummyTrans s?2DLXv}!
SELECT @Counter = @Counter + 1 5r$X
END H"g$qSx
EXEC (@TruncLog) Lk-%I?
END jW G=k#WN
SELECT 'Final Size of ' + db_name() + ' LOG is ' + UOg4E
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + =CE(M},d
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ca!=D $
FROM sysfiles \\WIu?
WHERE name = @LogicalFileName |4F3Gu
DROP TABLE DummyTrans g+-=/Ge
SET NOCOUNT OFF t#0/_tD
8、说明:更改某个表 !w[io;
exec sp_changeobjectowner 'tablename','dbo' Ve1O<i
9、存储更改全部表 J} 03 5
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 0{O|o_
@OldOwner as NVARCHAR(128), 1{.=T&eG#
@NewOwner as NVARCHAR(128) ]757oAXl
AS s]X]jfA.
DECLARE @Name as NVARCHAR(128) "1U:qr2-H
DECLARE @Owner as NVARCHAR(128) r9a?Y!(
DECLARE @OwnerName as NVARCHAR(128) :.+?v*%;n
DECLARE curObject CURSOR FOR Pkm3&sW
select 'Name' = name, AV0C9a/td
'Owner' = user_name(uid) .Fy f4^0
from sysobjects +P&;cCV`S3
where user_name(uid)=@OldOwner r`THOj\cM
order by name [,F5GW{x
OPEN curObject _l`s}yC
FETCH NEXT FROM curObject INTO @Name, @Owner zLs[vg.(
WHILE(@@FETCH_STATUS=0) M=}vDw]Q
BEGIN I#]$H#}Av
if @Owner=@OldOwner ;!CYp;_
begin -'tgr6=|w"
set @OwnerName = @OldOwner + '.' + rtrim(@Name) \?bp^BrI
exec sp_changeobjectowner @OwnerName, @NewOwner 4I>I
end e6n^l$'
-- select @name,@NewOwner,@OldOwner ?\QEK
FETCH NEXT FROM curObject INTO @Name, @Owner 4DL;/Z:
END 2[\I{<2/9
close curObject 1|L3} 2
deallocate curObject Om%9 x
GO );^]
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10、SQL SERVER中直接循环写入数据 CL^MIcq?
declare @i int !,*#e
set @i=1 2/9P&c-r