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。 Qop,~yK
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一、基础 kzDN(_<1
1、说明:创建数据库 HdJ g
CREATE DATABASE database-name %BP>,E/w
2、说明:删除数据库 k[;)/LfhS
drop database dbname <\u3p3"[4
3、说明:备份sql server IrqM_OjC
--- 创建 备份数据的 device oDz|%N2s|
USE master E)gD"^rex
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' R=lw}jH [Z
--- 开始 备份 ;*M@LP{*L
BACKUP DATABASE pubs TO testBack dD=$$(
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4、说明:创建新表 a3tcLd|7J
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 89g
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根据已有的表创建新表: JfIXv
A:create table tab_new like tab_old (使用旧表创建新表) MK=oGzK
B:create table tab_new as select col1,col2... from tab_old definition only 0lg$zi x(
5、说明:删除新表
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drop table tabname ~\jP+[>M'
6、说明:增加一个列 V0>X2&.A
Alter table tabname add column col type ]VRa4ZB{u
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。 Qs6Vu)U=
7、说明:添加主键: Alter table tabname add primary key(col) 5M0Q'"`F:
说明:删除主键: Alter table tabname drop primary key(col) L(VFzPkY%
8、说明:创建索引:create [unique] index idxname on tabname(col....) bOFzq>k_
删除索引:drop index idxname f\]?,
注:索引是不可更改的,想更改必须删除重新建。 <gkE,e9
9、说明:创建视图:create view viewname as select statement alaL/p{O
删除视图:drop view viewname FklR!*oL,)
10、说明:几个简单的基本的sql语句 xR/CP.dg
选择:select * from table1 where 范围 G`Nw]_
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插入:insert into table1(field1,field2) values(value1,value2) m9DFnk<D
删除:delete from table1 where 范围 }kqh[`:
更新:update table1 set field1=value1 where 范围 ,PTM'O@aU#
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! *9^8NY]
排序:select * from table1 order by field1,field2 [desc] ahg:mlaob
总数:select count as totalcount from table1 A'DFY {
求和:select sum(field1) as sumvalue from table1 3' i6<
平均:select avg(field1) as avgvalue from table1 E1eGZ&&Gd
最大:select max(field1) as maxvalue from table1 wtY)(ka
最小:select min(field1) as minvalue from table1 sFTAE1|
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11、说明:几个高级查询运算词 ?e$&=FC0;
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A: UNION 运算符 .B:ZyTI
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。 9&n9J^3L
B: EXCEPT 运算符 J:yv82
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。 [a2]_]E%
C: INTERSECT 运算符 b>;?{
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。 | ys5.|
注:使用运算词的几个查询结果行必须是一致的。 ga5Q
12、说明:使用外连接 9\_AB.Z:
A、left outer join: /?'~`4!(
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。 ("2X8(3z
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 M:/NW-:
B:right outer join: {EoYU\x
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。 .Vbd-jr'M
C:full outer join: n1."Qix0
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。 .SD-6GVD
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二、提升 'x*C#mt
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) bY" zK',m
法一:select * into b from a where 1<>1 $oBs%.Jp
法二:select top 0 * into b from a _QL|pLf-
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) !kovrvM6F
insert into b(a, b, c) select d,e,f from b; ba|xf@=&
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) K81X32Lm'
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 D&%8JL
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. o08WC'bX
4、说明:子查询(表名1:a 表名2:b) |g&V? lI
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) Lv%3 jj
5、说明:显示文章、提交人和最后回复时间 J3eud}w
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 8;@y\0
6、说明:外连接查询(表名1:a 表名2:b) FEjO}lTK
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c *7xcwjeP
7、说明:在线视图查询(表名1:a ) oy^-?+
select * from (SELECT a,b,c FROM a) T where t.a > 1; $hhXsu=
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 XV]N}~h o`
select * from table1 where time between time1 and time2 sgfqIe1
select a,b,c, from table1 where a not between 数值1 and 数值2 %R0 Wq4}
9、说明:in 的使用方法 &=g3J4$z
select * from table1 where a [not] in ('值1','值2','值4','值6') :#YC_
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 |?T=4~b
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 2{79,Js0
11、说明:四表联查问题: DBAyc#
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 ..... U@OdQAX
12、说明:日程安排提前五分钟提醒 QLY;@-jF$
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Msqqjhoy
13、说明:一条sql 语句搞定数据库分页 ?Y4 +3`\x
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 x%viCkq
14、说明:前10条记录 Z/ q6Q#
select top 10 * form table1 where 范围 J@5iD
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.) <_YdN)x
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) u7< +)6-
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 D$}hoM1
(select a from tableA ) except (select a from tableB) except (select a from tableC) X30tO>
17、说明:随机取出10条数据 m_)-
select top 10 * from tablename order by newid() wN[lC|1c
18、说明:随机选择记录 #X-C~*|>j
select newid() dn
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19、说明:删除重复记录 g *Js4
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Cbff:IP
20、说明:列出数据库里所有的表名 5#.m'a)
select name from sysobjects where type='U' Jt8;ddz
21、说明:列出表里的所有的 t2dsYU/
select name from syscolumns where id=object_id('TableName') sX1DbEjj[o
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 9JA@m
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type w"'
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显示结果: 6>]_H(z7
type vender pcs V4,Gt]4
电脑 A 1 6Z_V,LD9L
电脑 A 1 a|t~&\@
光盘 B 2
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光盘 A 2 PuNL%D
手机 B 3 X:W\EeH
手机 C 3 ; J W]b]
23、说明:初始化表table1 )E9!m
TRUNCATE TABLE table1 2.v{W-D[
24、说明:选择从10到15的记录 v9f+ {Y%-
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc jEBn"]\D
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三、技巧 \!^=~` X-
1、1=1,1=2的使用,在SQL语句组合时用的较多 >?^oxB"<Gc
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 5M5Bm[X
如: |S8$NI2
if @strWhere !='' wkp2A18n
begin fI`Ez!w0
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere A%D'Z85
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end !aT:0m$:9c
else %0Ur3
begin &~_F2]oM
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' -}6ew@GE
end p/Ul[7A4e
我们可以直接写成 KU8,8:yY
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere @aS)=|Ls\
2、收缩数据库 yJ?=##
--重建索引 1V2]@VQF
DBCC REINDEX |=q~X}DA
DBCC INDEXDEFRAG w9|x{B
--收缩数据和日志 c+FTt(\8.
DBCC SHRINKDB .n7@$kq
DBCC SHRINKFILE HYdM1s6vo
3、压缩数据库 sQgz}0_=)
dbcc shrinkdatabase(dbname) (.#nl}fA
4、转移数据库给新用户以已存在用户权限 X_78;T)uA
exec sp_change_users_login 'update_one','newname','oldname' J1w[gf]J
go fG0ZVV!
5、检查备份集 KdoI
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' a>v *
6、修复数据库 do8[wej<:
ALTER DATABASE [dvbbs] SET SINGLE_USER /r7xA}se^
GO ?}Zo~]7E
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK # xO PF9
GO [5&k{*}}
ALTER DATABASE [dvbbs] SET MULTI_USER `CWhjL8^
GO yr%[IX]R
7、日志清除 .)/."V
SET NOCOUNT ON m7k }k)
DECLARE @LogicalFileName sysname, fqI67E$59
@MaxMinutes INT, lAnq2j|
@NewSize INT GQ1/pys
USE tablename -- 要操作的数据库名 ]gBnzh.
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. v]SxZLa
@NewSize = 1 -- 你想设定的日志文件的大小(M) )WoH>D
-- Setup / initialize ST{Vi';}
DECLARE @OriginalSize int a_Xwi:e<
SELECT @OriginalSize = size .=eEuH
FROM sysfiles zQ+Mu^|u+
WHERE name = @LogicalFileName D9+qT<ojN
SELECT 'Original Size of ' + db_name() + ' LOG is ' + JMB#KzvN[
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + XZ%[;[
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 1'f_C<.0
FROM sysfiles |:C0_`M9
WHERE name = @LogicalFileName s)WA9PiC
CREATE TABLE DummyTrans 9n(68|^$
(DummyColumn char (8000) not null) v?."`,e
DECLARE @Counter INT, V0^{Ss1M
@StartTime DATETIME, C+'-TLeu
@TruncLog VARCHAR(255) ^}P94( oz
SELECT @StartTime = GETDATE(), (7qlp*8.s
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' nXn@|J&z~U
DBCC SHRINKFILE (@LogicalFileName, @NewSize) $.D)Llcq
EXEC (@TruncLog) qWH^/o
-- Wrap the log if necessary. i(%2t(wf+
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired K<^p~'f4P
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) g>t1rZ
AND (@OriginalSize * 8 /1024) > @NewSize bll[E}E|3
BEGIN -- Outer loop. o-bH3Jkb]&
SELECT @Counter = 0 6>]
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) g**!'T4&o
BEGIN -- update OJu>#
INSERT DummyTrans VALUES ('Fill Log') @aQ:3/
DELETE DummyTrans :a{dWgN
SELECT @Counter = @Counter + 1 ''auu4vF
END K/zb6=->
EXEC (@TruncLog) zr!7*,
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END 93*d:W8Vr
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Dn)yBA%
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + tU?BR<q
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' U,!qNi}
FROM sysfiles ]EHsRd
WHERE name = @LogicalFileName q0}u%Yz
DROP TABLE DummyTrans =@d#@
SET NOCOUNT OFF CcUF)$kz
8、说明:更改某个表 w1I07 (
exec sp_changeobjectowner 'tablename','dbo' FO/cEu
9、存储更改全部表 z%E(o%l8
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Tw';;euw
@OldOwner as NVARCHAR(128), KKsVZ~<6u
@NewOwner as NVARCHAR(128) ^N^G?{EV/#
AS sUlf4<_zW
DECLARE @Name as NVARCHAR(128) ow'G&<0b
DECLARE @Owner as NVARCHAR(128) HrE, K\^
DECLARE @OwnerName as NVARCHAR(128) )n)AmNpq
DECLARE curObject CURSOR FOR 7G+!9^
select 'Name' = name, S*<J y(:n
'Owner' = user_name(uid) ou-#+Sdd
from sysobjects ,marNG
where user_name(uid)=@OldOwner ZP~H!
order by name ZV--d'YiEm
OPEN curObject sgOau\E
FETCH NEXT FROM curObject INTO @Name, @Owner XMS:F]HN
WHILE(@@FETCH_STATUS=0) no8\Oees
BEGIN "_&ZRcd*
if @Owner=@OldOwner Y$>NsgQn6
begin /Pextj<
set @OwnerName = @OldOwner + '.' + rtrim(@Name) E0I/]0
exec sp_changeobjectowner @OwnerName, @NewOwner _]@u)$
end cD]H~D}M
-- select @name,@NewOwner,@OldOwner DY#195H
FETCH NEXT FROM curObject INTO @Name, @Owner F'|K>!H
END }Hb0@
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close curObject /)kJ iV
deallocate curObject ?lkB{-%rQ
GO \i+AMduAo
10、SQL SERVER中直接循环写入数据 EPJ>@A>;D
declare @i int `V9bd}M%~;
set @i=1 d:hnb)I$*
while @i<30 (-$5YKm
begin bVz<8b6h'-
insert into test (userid) values(@i) +c/!R|h=S
set @i=@i+1 &wlD`0v
end G2N0'R"
小记存储过程中经常用到的本周,本月,本年函数 8SU0q9X.
Dateadd(wk,datediff(wk,0,getdate()),-1) a+HK
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Dateadd(wk,datediff(wk,0,getdate()),6) O#k; O*s'
Dateadd(mm,datediff(mm,0,getdate()),0) {XIpHr
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) *` mxv0w~(
Dateadd(yy,datediff(yy,0,getdate()),0) b_`h2dUq
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) !D F~]&
上面的SQL代码只是一个时间段 6fw7\u
Dateadd(wk,datediff(wk,0,getdate()),-1) Y:/p0o
Dateadd(wk,datediff(wk,0,getdate()),6) J;~YD$
就是表示本周时间段. Aa_@&e
下面的SQL的条件部分,就是查询时间段在本周范围内的: [;Ih I
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 2 T} >9X
而在存储过程中 rrz([2E2
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) \)5mO 8w
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) YCE *Dm