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。 '-,$@l#
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一、基础 ;+Dq3NE
1、说明:创建数据库 As}eI!
CREATE DATABASE database-name ?Iin/ <y
2、说明:删除数据库 9wTN*y
drop database dbname >3C4S
3、说明:备份sql server {h}0"5
--- 创建 备份数据的 device z[cs/x
USE master Jw4#u5$$Z
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ^vj}
--- 开始 备份 s~z~9#G(6
BACKUP DATABASE pubs TO testBack B~CdY}UTsj
4、说明:创建新表 & t.G4
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 5[[mS
根据已有的表创建新表: r_x|2 AoO
A:create table tab_new like tab_old (使用旧表创建新表) ~E8L,h~
B:create table tab_new as select col1,col2... from tab_old definition only #JAy
5、说明:删除新表 wHT]&fZ
drop table tabname {4y#+[
6、说明:增加一个列 ?W3l
Alter table tabname add column col type mTj?W$+r
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 H@'f=Y*D
7、说明:添加主键: Alter table tabname add primary key(col) xg^Z. q)d
说明:删除主键: Alter table tabname drop primary key(col) (^G@-eh
8、说明:创建索引:create [unique] index idxname on tabname(col....) 9hTzi+'S
删除索引:drop index idxname f?qp*
注:索引是不可更改的,想更改必须删除重新建。 /<R[X>]<F
9、说明:创建视图:create view viewname as select statement mA?fCs
删除视图:drop view viewname 8|"26UwD/
10、说明:几个简单的基本的sql语句 iwXMe(k
选择:select * from table1 where 范围 tl=H9w&@
插入:insert into table1(field1,field2) values(value1,value2) 1_jd1UT
删除:delete from table1 where 范围 rjo1
更新:update table1 set field1=value1 where 范围 N^TE
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! @Y&UP
排序:select * from table1 order by field1,field2 [desc] '!DS3zEeLS
总数:select count as totalcount from table1 joRrsxFU
求和:select sum(field1) as sumvalue from table1 NQmdEsK
平均:select avg(field1) as avgvalue from table1 sGp]jqX2,m
最大:select max(field1) as maxvalue from table1 ^[6S]Ft(
最小:select min(field1) as minvalue from table1 SWLt5dV
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11、说明:几个高级查询运算词 -cONC9=
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A: UNION 运算符 E*Z # fa
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 }T~}W8H
B: EXCEPT 运算符 [S_qi,
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 iD${7
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C: INTERSECT 运算符 `3e>JIl"0
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。 Wb%t6N?
注:使用运算词的几个查询结果行必须是一致的。 -<{;.~nI.
12、说明:使用外连接 ,+>JQ82
A、left outer join: PC<[$~
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 s L=}d[
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 1PUeU+
B:right outer join: EY^+ N>
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 1=Z, #r
C:full outer join: rizWaw5E!8
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 .Cz9?]jyI
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二、提升 Fl}{"eCF8
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) <}Hs@`jS
法一:select * into b from a where 1<>1 n)uck5
法二:select top 0 * into b from a M-V{(
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) \\)9QP?
insert into b(a, b, c) select d,e,f from b; O63:t$Yx#
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) m>9j dsqB
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 9SQcChG~j
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. fZgEJsr
4、说明:子查询(表名1:a 表名2:b) L}\ oFjVju
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) EM7Z g 65
5、说明:显示文章、提交人和最后回复时间 f
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b AF\gB2^
6、说明:外连接查询(表名1:a 表名2:b) _Q9I
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c z=6zc-$y 9
7、说明:在线视图查询(表名1:a ) !T"jvDYH
select * from (SELECT a,b,c FROM a) T where t.a > 1; IwVdx^9
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 H(gETRh
select * from table1 where time between time1 and time2 ae>B0#=
select a,b,c, from table1 where a not between 数值1 and 数值2 LEC=@) B
9、说明:in 的使用方法 I&9Itn p$
select * from table1 where a [not] in ('值1','值2','值4','值6') '\% Kd+k
10、说明:两张关联表,删除主表中已经在副表中没有的信息 E}g)q;0v|2
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 8'*/|)Hn
11、说明:四表联查问题: 8P*d
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 ..... `kYcTFk
12、说明:日程安排提前五分钟提醒 s3[\&zt
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 eL_Il.:
13、说明:一条sql 语句搞定数据库分页 |"
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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 U[{vA6
14、说明:前10条记录 aP[oLk$'Z
select top 10 * form table1 where 范围 a7}O.NDf
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) yHf:/8Z
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ~0Z.,p_
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 KA? J:
(select a from tableA ) except (select a from tableB) except (select a from tableC) WRp0.
17、说明:随机取出10条数据 uI\6":/u
select top 10 * from tablename order by newid() Yy'CBIq#f
18、说明:随机选择记录 l.xKv$uOGR
select newid() kfgkZ"9
19、说明:删除重复记录 [=TD)o>W(p
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) )lH`a
20、说明:列出数据库里所有的表名 7d^ ~.F
select name from sysobjects where type='U' _>E=.$
21、说明:列出表里的所有的 @y2cC6+'t
select name from syscolumns where id=object_id('TableName') fb8)jd'~}O
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。 !;Vqs/E
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 X?.tj
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显示结果: MNf^ml[
type vender pcs 1G8,Eah
电脑 A 1 Vt(s4
电脑 A 1 Ip|=NQL>
光盘 B 2 k_`h (R
光盘 A 2 ?|Ey WAL
手机 B 3 UaB2vuL*=
手机 C 3 j@R"AP}
23、说明:初始化表table1 #~ZaN;u
TRUNCATE TABLE table1 @a i2A|
24、说明:选择从10到15的记录 9y*2AaxW
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 5KTPlqm0qF
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三、技巧 ?4#UW7I
1、1=1,1=2的使用,在SQL语句组合时用的较多 srhI%Zj
"where 1=1" 是表示选择全部 "where 1=2"全部不选, dVSQG947i:
如: Pq,iR J
if @strWhere !='' ue*o>iohB
begin
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere $;rvKco)%
end W[:CCCDL
else `<-/e%8
begin <k 'zz:[c!
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' s6k(K>Pl
end *).!
我们可以直接写成 1&RB=7.h
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere m=25HH7enb
2、收缩数据库 M'VJE|+t
--重建索引
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DBCC REINDEX Xp9 ]
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DBCC INDEXDEFRAG tgj5l#P
--收缩数据和日志 LIll@2[
DBCC SHRINKDB @0V4$OoFl
DBCC SHRINKFILE &g~NkJc0c
3、压缩数据库 LqLhZBU9
dbcc shrinkdatabase(dbname) ZK h4:D
4、转移数据库给新用户以已存在用户权限 .,f]'!5
exec sp_change_users_login 'update_one','newname','oldname' Z7I\\M
go yL %88,/
5、检查备份集 <cxe
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' <cO
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6、修复数据库 [6Q1yNE
ALTER DATABASE [dvbbs] SET SINGLE_USER M)~sL1)
GO -O\fy!
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK BO2s(8
GO R$`%<Y3)
ALTER DATABASE [dvbbs] SET MULTI_USER xDNXI01o
GO @hwNM#>`
7、日志清除 M+I9k;N6&
SET NOCOUNT ON ,/&|:PkS
DECLARE @LogicalFileName sysname, JNo[<SZb
@MaxMinutes INT, ^<_rE- k
@NewSize INT CjEzsjqe<I
USE tablename -- 要操作的数据库名 ' g d=\gV
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 UOyM=#ipY
@MaxMinutes = 10, -- Limit on time allowed to wrap log. UW1i%u
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@NewSize = 1 -- 你想设定的日志文件的大小(M) 51-'*Y
-- Setup / initialize }0sLeGJ!
DECLARE @OriginalSize int 5"ooam3
SELECT @OriginalSize = size y&/bp<Z
FROM sysfiles MnlD87x@X
WHERE name = @LogicalFileName b~2LD3"3
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 6z]y
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + WD1>{TSn
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 1'P4{T0 [
FROM sysfiles bokr,I3
WHERE name = @LogicalFileName _9dW+
CREATE TABLE DummyTrans z4(`>z2a
(DummyColumn char (8000) not null) 2O- 4x
DECLARE @Counter INT, 9I*2xy|I
@StartTime DATETIME, Ta$55K0
@TruncLog VARCHAR(255) uw/N`u
SELECT @StartTime = GETDATE(), Sk-Q 4D^
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Lyz8DwZ
DBCC SHRINKFILE (@LogicalFileName, @NewSize) U'u_'5{
EXEC (@TruncLog) ~NB|BwAh
-- Wrap the log if necessary. CM7NdK?I
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired \58bz<u"
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) U "r)C;5
AND (@OriginalSize * 8 /1024) > @NewSize ss6{+@,
BEGIN -- Outer loop. ky&wv+7
SELECT @Counter = 0 o_BRsJy
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) #=)!\
BEGIN -- update dc0&*/`:
INSERT DummyTrans VALUES ('Fill Log') ^rd%{6m
DELETE DummyTrans GQjwr(
SELECT @Counter = @Counter + 1 Vl3-cW@p
END Z>l|R C
EXEC (@TruncLog) @6Lp$w
END ~dzD7lG6
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ]~~G<Yh:=
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + g W_E
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' t/_\w"
FROM sysfiles =[zP
WHERE name = @LogicalFileName ^nK 7&]rK
DROP TABLE DummyTrans DWEDL[{
SET NOCOUNT OFF e1y#p3 @d
8、说明:更改某个表 7w]3D
exec sp_changeobjectowner 'tablename','dbo' N|%r5%
9、存储更改全部表 =k,?+h~
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch :iGK9I
@OldOwner as NVARCHAR(128), ,N;2"$+E
@NewOwner as NVARCHAR(128) dkY JO!
AS =M}tet
}
DECLARE @Name as NVARCHAR(128) It<VjN9
DECLARE @Owner as NVARCHAR(128) bxzx@sF2l
DECLARE @OwnerName as NVARCHAR(128) e"*1l>g
DECLARE curObject CURSOR FOR $:# :"
select 'Name' = name, w~:F?
'Owner' = user_name(uid) 6(x53y__
from sysobjects aXzb]">
where user_name(uid)=@OldOwner vxug>2
order by name =qbN?a/?2
OPEN curObject lMG+,?<uK&
FETCH NEXT FROM curObject INTO @Name, @Owner 1GIBqs~-
WHILE(@@FETCH_STATUS=0) X&h?1lMJ /
BEGIN n).*=YLN
if @Owner=@OldOwner KUq7O a!
begin mU
set @OwnerName = @OldOwner + '.' + rtrim(@Name) "shX~zd5
exec sp_changeobjectowner @OwnerName, @NewOwner WnOvU<Z
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end 'Z:wEt!
-- select @name,@NewOwner,@OldOwner KFRf5^ %
FETCH NEXT FROM curObject INTO @Name, @Owner J"@X>n
END ';!-a]N
close curObject }p-/R'
deallocate curObject 54B`T/>R:E
GO ZJ~0o2xZ'
10、SQL SERVER中直接循环写入数据 .z=%3p8+
declare @i int !
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set @i=1 ~H:=p
while @i<30 U&=pKbTe
begin 8aC=k@YE
insert into test (userid) values(@i) _n!>*A!
set @i=@i+1 Kv9FqrDj
end ~:PM_o*6
小记存储过程中经常用到的本周,本月,本年函数 oO`a {n-
Dateadd(wk,datediff(wk,0,getdate()),-1) 4)>UTMF
Dateadd(wk,datediff(wk,0,getdate()),6) %Ofw"W
Dateadd(mm,datediff(mm,0,getdate()),0) 3aBE[
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) @'5*jXd
Dateadd(yy,datediff(yy,0,getdate()),0) ^Sj;~
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 4 P=1)t?tX
上面的SQL代码只是一个时间段 ,G-
Dateadd(wk,datediff(wk,0,getdate()),-1) w c~s:
Dateadd(wk,datediff(wk,0,getdate()),6) mP/#hwzB&q
就是表示本周时间段. $CJf 0[|
下面的SQL的条件部分,就是查询时间段在本周范围内的: >8x)\'w
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) /d">}%Jn
而在存储过程中 SSTn|
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) *M*WjEOA
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) xWqV~NnE