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。 F:DrX_O%
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一、基础 wy2
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1、说明:创建数据库 /Z4et'Lo
CREATE DATABASE database-name 3Zh)]^
2、说明:删除数据库 ;dhQN}7
drop database dbname ?Mfw]z"\C)
3、说明:备份sql server hE-M$LmN@
--- 创建 备份数据的 device g9F?z2^
USE master 2:ylv<\$
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Z3!`J&
--- 开始 备份 "kF g
BACKUP DATABASE pubs TO testBack >
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4、说明:创建新表 |ENh)M8}r
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) +"VP-s0
根据已有的表创建新表: hpk7 Anp
A:create table tab_new like tab_old (使用旧表创建新表) 8dhUBJ0_
B:create table tab_new as select col1,col2... from tab_old definition only FN73+-:n:j
5、说明:删除新表 bZV/l4TU
drop table tabname !|>"o7
6、说明:增加一个列 >LuYHr
Alter table tabname add column col type 9cm#56
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 zx7{U8*`<
7、说明:添加主键: Alter table tabname add primary key(col) @lph)A Nk
说明:删除主键: Alter table tabname drop primary key(col) 3+bt~J0
8、说明:创建索引:create [unique] index idxname on tabname(col....) Ga'swP=hf
删除索引:drop index idxname L/^I*p,
注:索引是不可更改的,想更改必须删除重新建。 ct}9i"H#1
9、说明:创建视图:create view viewname as select statement Rx}Gz$
删除视图:drop view viewname qIqM{#' ^
10、说明:几个简单的基本的sql语句 PUX;I0Cf
选择:select * from table1 where 范围 v.5+7,4
插入:insert into table1(field1,field2) values(value1,value2) u<&m]]*
删除:delete from table1 where 范围 DlNX 3
更新:update table1 set field1=value1 where 范围 WuW^GC{7
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! uW3!Yg@
排序:select * from table1 order by field1,field2 [desc] ;9g2?-svw
总数:select count as totalcount from table1 Q NVa?'0"Y
求和:select sum(field1) as sumvalue from table1 Sa5G.^XI
平均:select avg(field1) as avgvalue from table1 @\I#^X5lv
最大:select max(field1) as maxvalue from table1 FxtI"g\0
最小:select min(field1) as minvalue from table1 dcT80sOC
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11、说明:几个高级查询运算词 &jr3B;g!C
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A: UNION 运算符 &iVs0R
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。 HUO j0T
B: EXCEPT 运算符 xn|(9#1o
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。 L&OwPd
C: INTERSECT 运算符 \5cpFj5%
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。 OK
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注:使用运算词的几个查询结果行必须是一致的。 jlg(drTo
12、说明:使用外连接 dAe')N:KPI
A、left outer join: '[O;zJN;
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。 C2)2)
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 k-""_WJ~^
B:right outer join: 2VCI 1E
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。 P
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C:full outer join: H7+,*
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。 FU<Jp3<%
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二、提升 gKCX|cULY
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) G9@0@2aY8
法一:select * into b from a where 1<>1 d*Fj3Wkx
法二:select top 0 * into b from a G<;*SYAb
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) uA#;G/$
insert into b(a, b, c) select d,e,f from b; eKqk= (
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) 5i{j' {_(8
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 f'3$9x
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. _n\GNUA
4、说明:子查询(表名1:a 表名2:b) ?@
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select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 9@)O_@=
5、说明:显示文章、提交人和最后回复时间 Q.c\/&
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b N$:8,9.z
6、说明:外连接查询(表名1:a 表名2:b) 7i1q wRv
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c t@+}8^M
7、说明:在线视图查询(表名1:a ) 9k[9P;"F:
select * from (SELECT a,b,c FROM a) T where t.a > 1; !_Z&a
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.J.RE"M
select * from table1 where time between time1 and time2 jOD?|tK&
select a,b,c, from table1 where a not between 数值1 and 数值2 "Os_vlapHo
9、说明:in 的使用方法 zs#@jv$
select * from table1 where a [not] in ('值1','值2','值4','值6') iMRwp+$
10、说明:两张关联表,删除主表中已经在副表中没有的信息 u08mqEa
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 1 I",L&S1
11、说明:四表联查问题: {P#|zp 4C{
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 ..... 0S$N05
12、说明:日程安排提前五分钟提醒 TrR8?-
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 g95`.V}
13、说明:一条sql 语句搞定数据库分页 6/dI6C!
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 7W.~
14、说明:前10条记录 @49S`
select top 10 * form table1 where 范围 !m?-!:
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) i8HTzv"J
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) `,*5wBC
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 P J[`|
(select a from tableA ) except (select a from tableB) except (select a from tableC) =[jXe
17、说明:随机取出10条数据 }|5Pr(I
select top 10 * from tablename order by newid() 4tmAzD
18、说明:随机选择记录 ^@NU}S):yN
select newid() ?=fyc1
19、说明:删除重复记录 t}tEvh
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) xWQ`tWA:J
20、说明:列出数据库里所有的表名 t}/( b/VD
select name from sysobjects where type='U' jsi!fx2Rm
21、说明:列出表里的所有的 OprkR
select name from syscolumns where id=object_id('TableName') x;<W&s}(
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 Q#[9|A9
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type ijx0gh`~
显示结果: 6<(.4a?
type vender pcs {h`uV/5@`
电脑 A 1 nwCrZW
电脑 A 1 sZF6h=67D
光盘 B 2 e6RPIg
光盘 A 2 Hc(OI|z~
手机 B 3 o J;$sj
手机 C 3 "OnGE$
23、说明:初始化表table1
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TRUNCATE TABLE table1 ~zNAbaC+>t
24、说明:选择从10到15的记录 hTi$.y!k
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc L8#5*8W6
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三、技巧 P3 ^Y"Pv?
1、1=1,1=2的使用,在SQL语句组合时用的较多 (0y~%J
"where 1=1" 是表示选择全部 "where 1=2"全部不选, NGO fb
如: (;^syJrh
if @strWhere !='' ]}2ZttQ?
begin )~ h}
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere #"iu|D
end x>`%DwoRI
else E\pL!c
begin C/6V9;U
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' j^rIH#V
end i9][N5\$
我们可以直接写成 HJYScwjQ;`
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere M} v/tRI
2、收缩数据库 >]5P
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--重建索引 >>fH{/l
DBCC REINDEX 0T5L_%c
DBCC INDEXDEFRAG L AAHEv
--收缩数据和日志 :y jKL^G>
DBCC SHRINKDB L<{i,'M
DBCC SHRINKFILE
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3、压缩数据库 |R\>@Mg#B
dbcc shrinkdatabase(dbname) 2'MZ s]??w
4、转移数据库给新用户以已存在用户权限 v9O~@v{=
exec sp_change_users_login 'update_one','newname','oldname'
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go 2JcjZn
5、检查备份集 [!]2djc
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' GD_hhDyD
6、修复数据库 *CTlOy
ALTER DATABASE [dvbbs] SET SINGLE_USER P:]^rke~&
GO O2dW6bt
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK g0ly
GO 7 X'u6$i
ALTER DATABASE [dvbbs] SET MULTI_USER i|*)I:SHU
GO gz#i.-
7、日志清除 1gN=-AC
SET NOCOUNT ON CDR@
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DECLARE @LogicalFileName sysname, :I^;jdL
@MaxMinutes INT, ):_\;.L
@NewSize INT 6h,(wo3Y
USE tablename -- 要操作的数据库名 ~d*(=G
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 uurh??R
@MaxMinutes = 10, -- Limit on time allowed to wrap log. T&o(N3lW
@NewSize = 1 -- 你想设定的日志文件的大小(M) !fR3(=oN
-- Setup / initialize +jnJ|h({
DECLARE @OriginalSize int DG ;_Vg
SELECT @OriginalSize = size Opc
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FROM sysfiles 1rF]yi:X
WHERE name = @LogicalFileName ly_HWuFJ3
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 9b"=9y,
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 0Bi.6r
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 91-o}|3v
FROM sysfiles OCaq3_#tZ
WHERE name = @LogicalFileName A='N=^Pm
CREATE TABLE DummyTrans 0+ ;bh
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(DummyColumn char (8000) not null) !SdSE^lz`
DECLARE @Counter INT, 3!oi +_
@StartTime DATETIME, @?
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@TruncLog VARCHAR(255) kw%};;
SELECT @StartTime = GETDATE(), Vi]W |bP
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' LKOwxF#TKT
DBCC SHRINKFILE (@LogicalFileName, @NewSize) aa#Y=%^
EXEC (@TruncLog) (w/T-*
-- Wrap the log if necessary. "~7>\>UFh
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 5T2CISmu
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) v8[I8{41
AND (@OriginalSize * 8 /1024) > @NewSize +kO!Xc%P&
BEGIN -- Outer loop. '2nhv,|.U
SELECT @Counter = 0 <;m<8RjX
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) cir$voL
BEGIN -- update 1A G<$d5U|
INSERT DummyTrans VALUES ('Fill Log') T)TfB(
DELETE DummyTrans "wnzo,
SELECT @Counter = @Counter + 1 b
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END .e=:RkI,
EXEC (@TruncLog) ';jYOVe
END %9N7Ln|%
SELECT 'Final Size of ' + db_name() + ' LOG is ' + k_5L4c:"
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + vMt/u?oB
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' EGzzHIZ`!
FROM sysfiles *|C^=*j9
WHERE name = @LogicalFileName +|'c>,?2H
DROP TABLE DummyTrans Vjp1RWb
SET NOCOUNT OFF dDGgvi|[Mz
8、说明:更改某个表 s!c`=
exec sp_changeobjectowner 'tablename','dbo' -Rd/Gx
9、存储更改全部表 (#Gw1
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch MmnOHN@.
@OldOwner as NVARCHAR(128), ]#l/2V1
@NewOwner as NVARCHAR(128) (@<c6WS
AS ,p2s:&"
DECLARE @Name as NVARCHAR(128) KB`!Sj\
DECLARE @Owner as NVARCHAR(128) Q$1bWUS&
DECLARE @OwnerName as NVARCHAR(128) ;/fF,L{c
DECLARE curObject CURSOR FOR +*T7@1
select 'Name' = name, v99B7VH4
'Owner' = user_name(uid) E2@65b$
from sysobjects 1V4s<m>#
where user_name(uid)=@OldOwner "UGY2skf;
order by name 'y2nN=CN
OPEN curObject "2P&X
FETCH NEXT FROM curObject INTO @Name, @Owner +"cq(Y@
WHILE(@@FETCH_STATUS=0) 1#*a:F&re
BEGIN D2!X?"[P
if @Owner=@OldOwner , 5kKimTt
begin 5JCG2jqx0
set @OwnerName = @OldOwner + '.' + rtrim(@Name) -pa )K"z
exec sp_changeobjectowner @OwnerName, @NewOwner t.&Od;\[/
end gp^5#
-- select @name,@NewOwner,@OldOwner f3&[#%
FETCH NEXT FROM curObject INTO @Name, @Owner )-
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END @}OL9Ch
close curObject &7b|4a8B%
deallocate curObject [}/LD3
GO sCi s4gX.]
10、SQL SERVER中直接循环写入数据 =Z+nz^'b
declare @i int fA<[f
set @i=1 z4+k7a@jn
while @i<30 ?ROqn6k&c
begin 0]=i}wL 8
insert into test (userid) values(@i) >.'*)@vQi
set @i=@i+1 YN2sdG
end e8]\U/
小记存储过程中经常用到的本周,本月,本年函数 feNdMR7eM
Dateadd(wk,datediff(wk,0,getdate()),-1) ~Ro9up
Dateadd(wk,datediff(wk,0,getdate()),6) c^u"I'#Q
Dateadd(mm,datediff(mm,0,getdate()),0) #H{<gjs]
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) OCJnjlV%
Dateadd(yy,datediff(yy,0,getdate()),0) ? glSC$b
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) e~@[18
上面的SQL代码只是一个时间段 P%=#^T&`}
Dateadd(wk,datediff(wk,0,getdate()),-1) 2f:Eof(B
Dateadd(wk,datediff(wk,0,getdate()),6)
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就是表示本周时间段. C] 9p5Hs
下面的SQL的条件部分,就是查询时间段在本周范围内的: %D8ZO0J7H
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) < hO
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而在存储过程中 W#BM(I
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) @,u/w4
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) &)vC;$vD`