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。 PQ;9iv
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一、基础 kaoiSL<[6
1、说明:创建数据库 *5XOYb?'v.
CREATE DATABASE database-name xDPR^xY
2、说明:删除数据库 ?|Z~mE
drop database dbname UxF9Ko( ]d
3、说明:备份sql server sV0NDM0
--- 创建 备份数据的 device $*:$-
USE master w /PE )xA
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Lr
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--- 开始 备份 II=!E
BACKUP DATABASE pubs TO testBack dK8dC1@,X;
4、说明:创建新表 9pr.`w
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) f;OB"p
根据已有的表创建新表: :AQ9-&i/a-
A:create table tab_new like tab_old (使用旧表创建新表) 3 _!MVT
B:create table tab_new as select col1,col2... from tab_old definition only ,_<|e\>~
5、说明:删除新表 X(.[rC>
drop table tabname rXBCM
6、说明:增加一个列 JrX. f
Alter table tabname add column col type A@:U|)+4
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。 Nq6;
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7、说明:添加主键: Alter table tabname add primary key(col) !I&,!$
说明:删除主键: Alter table tabname drop primary key(col) P1^|r}
8、说明:创建索引:create [unique] index idxname on tabname(col....) 3xdJ<Lrq
删除索引:drop index idxname 5eyB\>k,
注:索引是不可更改的,想更改必须删除重新建。 QUZ+#*:s
9、说明:创建视图:create view viewname as select statement
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删除视图:drop view viewname z
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10、说明:几个简单的基本的sql语句 ly_8p63-
选择:select * from table1 where 范围 A>mk0P)~Q
插入:insert into table1(field1,field2) values(value1,value2) G^.tAO5:f
删除:delete from table1 where 范围 >lyE@S sA
更新:update table1 set field1=value1 where 范围 0r i
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 8<ev5af
排序:select * from table1 order by field1,field2 [desc] SXE@\Afj
总数:select count as totalcount from table1 (c"!&&S^ =
求和:select sum(field1) as sumvalue from table1 q
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平均:select avg(field1) as avgvalue from table1 R>&8%%#
最大:select max(field1) as maxvalue from table1 \L}7.fkb8
最小:select min(field1) as minvalue from table1 y!rJ}e
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11、说明:几个高级查询运算词 ^
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A: UNION 运算符 '{.8tT?tJ
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。 3^$=XrD
B: EXCEPT 运算符 ( *K)D$y
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。 b5KK0Jjk
C: INTERSECT 运算符 to1r
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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。 l[%=S!
注:使用运算词的几个查询结果行必须是一致的。 Lp4F1H2t-
12、说明:使用外连接 lOe|]pQ.,
A、left outer join: p8?"}
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。 nqTOAL9FF
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 ;i/? fw[h
B:right outer join: vCK+v
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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。 KDV.ZSF7
C:full outer join: a0 PU&o1EF
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。 z!.cc6R
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二、提升 _2}~Vqb+
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ?4aW^l6/
法一:select * into b from a where 1<>1 %q9"2]
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法二:select top 0 * into b from a T2tvU*[=
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) h^1!8oOYD
insert into b(a, b, c) select d,e,f from b; \I<R.49oW
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) "Y4glomR[
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Z#^|h0
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. [gZR}E
4、说明:子查询(表名1:a 表名2:b) gh
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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) 23,pVo
5、说明:显示文章、提交人和最后回复时间 J6>tGKa+e
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b cnw+^8
6、说明:外连接查询(表名1:a 表名2:b) 1,]FLsuy
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ro3%VA=V
7、说明:在线视图查询(表名1:a ) -xN/H,xok
select * from (SELECT a,b,c FROM a) T where t.a > 1; L
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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 5~im.XfiVx
select * from table1 where time between time1 and time2 0 VG;z#{J
select a,b,c, from table1 where a not between 数值1 and 数值2 @0NWc
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9、说明:in 的使用方法 sX*L[3!vN
select * from table1 where a [not] in ('值1','值2','值4','值6') EwuRIe;D
10、说明:两张关联表,删除主表中已经在副表中没有的信息 pjoyMHWK
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) loE;q}^
11、说明:四表联查问题: esQ`6i
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 ..... ]:']
12、说明:日程安排提前五分钟提醒 D@ !r?E`
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 _IV!9 JL
13、说明:一条sql 语句搞定数据库分页 DnG9bVm>
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 '.>y'=
14、说明:前10条记录 gN73)uJ0
select top 10 * form table1 where 范围 D`'Cnt/
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.) kUT^o
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) YU)%-V\
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 G]EI!-y
(select a from tableA ) except (select a from tableB) except (select a from tableC) 0w< ilJ
17、说明:随机取出10条数据 #`K {vj
select top 10 * from tablename order by newid() ue@W@pj
18、说明:随机选择记录 jt9- v-
select newid() >ke.ZZV?
19、说明:删除重复记录 oR,zr
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 5ug|crX
20、说明:列出数据库里所有的表名 ;volBfv
select name from sysobjects where type='U' }; M@JMu,
21、说明:列出表里的所有的 rwio>4=
select name from syscolumns where id=object_id('TableName') $/@
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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。 ZJF+./vN
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 `g)
显示结果: euRKYGW
type vender pcs GRVF/hPn
电脑 A 1 BSB&zp
电脑 A 1 qbCU&G|)
光盘 B 2 f1elzANy
光盘 A 2 :PY6J}:
手机 B 3 1CSGG'J]E
手机 C 3 ]\oT({$6B
23、说明:初始化表table1 1;i|GXY:h
TRUNCATE TABLE table1 4GG>n
24、说明:选择从10到15的记录 #n15_cd
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc bAN>\zG+
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三、技巧 j72mm!
1、1=1,1=2的使用,在SQL语句组合时用的较多 nHQ*#&$
"where 1=1" 是表示选择全部 "where 1=2"全部不选, .XRe:\8mc
如: @'GPZpbvZ
if @strWhere !='' F?6Q(mRl
begin *tk=D sRW
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere .O(9\3q\
end >j$aY
else i_*.
begin p5w9X+G%
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' #Ufb
end 1[#sHj$Na`
我们可以直接写成 1^V.L+0s]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Bg zq
2、收缩数据库 uudd'L
--重建索引 J7%rPJ
DBCC REINDEX 5} ur,0{
DBCC INDEXDEFRAG <sM_zoprc
--收缩数据和日志 U>bIQk"4
DBCC SHRINKDB .a(G=fk
DBCC SHRINKFILE }$qrNbLJ
3、压缩数据库 skTaIGRL
dbcc shrinkdatabase(dbname) f\Hw Y)^>
4、转移数据库给新用户以已存在用户权限 :A:7^jrhi
exec sp_change_users_login 'update_one','newname','oldname' *O @Zn
go !b4AeiL>w
5、检查备份集 @,;h!vB*=
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' m|x_++3
6、修复数据库 |`Yn'Mj8rm
ALTER DATABASE [dvbbs] SET SINGLE_USER {Oq8A.daJ
GO "UhE'\()
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK A
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GO N;BuBm5K
ALTER DATABASE [dvbbs] SET MULTI_USER RW1+y/#%P
GO v6Y[_1
7、日志清除 )Y'g;
SET NOCOUNT ON Ui9;rh$1eU
DECLARE @LogicalFileName sysname, ,{msJyacmR
@MaxMinutes INT, d)D!np=
@NewSize INT &m[}%e%~0
USE tablename -- 要操作的数据库名 02tN=}Cj)
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 -aE,KQ
@MaxMinutes = 10, -- Limit on time allowed to wrap log. F9r/
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@NewSize = 1 -- 你想设定的日志文件的大小(M) "rEfhzmyF
-- Setup / initialize jq8TfJ|
DECLARE @OriginalSize int 8fBhX,1
SELECT @OriginalSize = size *P]]7DR
FROM sysfiles .d$Q5Qae
WHERE name = @LogicalFileName '@w'(}3!3R
SELECT 'Original Size of ' + db_name() + ' LOG is ' + f}4A,%:1
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 2J$vX(
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' BhbfPQ
FROM sysfiles tlg}"lY
WHERE name = @LogicalFileName w^ofH-R/
CREATE TABLE DummyTrans aaN/HE_
(DummyColumn char (8000) not null) .3n\~Sn
DECLARE @Counter INT, ydY 7 :D
@StartTime DATETIME, $UK m[:7
@TruncLog VARCHAR(255) |22vNt_
SELECT @StartTime = GETDATE(), `'EG7
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' tl7:L>
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ^;( dF<?'r
EXEC (@TruncLog) 4b`Fi@J\
-- Wrap the log if necessary. "AKr;|m
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired %hZX XpuO
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) kq?:<!z
AND (@OriginalSize * 8 /1024) > @NewSize 3PL0bejaT7
BEGIN -- Outer loop. }lhk;#r
SELECT @Counter = 0 >=:mtcph
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) xN}f?
BEGIN -- update F1B/cd
INSERT DummyTrans VALUES ('Fill Log') u>agVB4\F
DELETE DummyTrans 8\:>;XG6f
SELECT @Counter = @Counter + 1 +ug/%Iay{k
END Ygkf}n
EXEC (@TruncLog) ?1Vx)j>|
END $F X$nY
SELECT 'Final Size of ' + db_name() + ' LOG is ' + gGBRfq>
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ~UQ<8`@a
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 5!$sQ@#}D
FROM sysfiles +opym!\
WHERE name = @LogicalFileName hJSWh5]
DROP TABLE DummyTrans -b8SaLak
SET NOCOUNT OFF VYh/URU>
8、说明:更改某个表 (4yXr|to}
exec sp_changeobjectowner 'tablename','dbo' d7QUg6=
9、存储更改全部表 @(E6P;+{
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch &2 *
@OldOwner as NVARCHAR(128), @"/H
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@NewOwner as NVARCHAR(128) '73}{" '
AS Qy4Pw\
DECLARE @Name as NVARCHAR(128) !v9`oL26
DECLARE @Owner as NVARCHAR(128) '/9MN;_
DECLARE @OwnerName as NVARCHAR(128) wxj}k7_(`A
DECLARE curObject CURSOR FOR QfPw50N;
select 'Name' = name, @W
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'Owner' = user_name(uid) )1@%!fr
from sysobjects Iw(
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where user_name(uid)=@OldOwner I!u=.[5zdC
order by name
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OPEN curObject OkISRj'!U
FETCH NEXT FROM curObject INTO @Name, @Owner IuAu_`,Ndi
WHILE(@@FETCH_STATUS=0) \pTC[Ry1
BEGIN O:T
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if @Owner=@OldOwner |*h{GX.(
begin ya^8mp-
set @OwnerName = @OldOwner + '.' + rtrim(@Name) C\Yf]J
exec sp_changeobjectowner @OwnerName, @NewOwner T3SFG]H
end yENAc sv
-- select @name,@NewOwner,@OldOwner /?XI,#j3kM
FETCH NEXT FROM curObject INTO @Name, @Owner \Zx&J.D
END EL z5P}L6
close curObject Ars*H,9>e
deallocate curObject f2SJ4"X
GO 4@<wN \'
10、SQL SERVER中直接循环写入数据 xE!0p EHd
declare @i int 8@S]P0lk
set @i=1 4tUt"N
while @i<30 n4 N6]W\5
begin #6[F&
insert into test (userid) values(@i) p8YOow7)
set @i=@i+1 Ik5V?
end ohJDu{V
小记存储过程中经常用到的本周,本月,本年函数 M}CxCEdDB]
Dateadd(wk,datediff(wk,0,getdate()),-1) !Yn#3c
Dateadd(wk,datediff(wk,0,getdate()),6) dhJ=+Fz"w
Dateadd(mm,datediff(mm,0,getdate()),0) }''0N1,/
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Lpkx$QZ
Dateadd(yy,datediff(yy,0,getdate()),0) ,2^A<IwR
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ;YMg4Cs
上面的SQL代码只是一个时间段 3$5E1*ed
Dateadd(wk,datediff(wk,0,getdate()),-1) ?P>4H0@I+
Dateadd(wk,datediff(wk,0,getdate()),6) u#^l9/tl
就是表示本周时间段. iPWr-
下面的SQL的条件部分,就是查询时间段在本周范围内的: w{*V8S3h9
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) @o'L! 5Y
而在存储过程中 83'+q((<
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) cwtlOg
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) (0`w.n