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。 ?c^0%Op
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一、基础 8:,l+[\
1、说明:创建数据库 X] &Q^
CREATE DATABASE database-name m>'sM1s
2、说明:删除数据库 }4kd=]Nk
drop database dbname ?j8F5(HF?
3、说明:备份sql server |,Y(YSg.
--- 创建 备份数据的 device ;%AK< RT
USE master xS`>[8?3<T
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' g Xvuv^
--- 开始 备份 kfBVF%90
BACKUP DATABASE pubs TO testBack VZ;ASA?;
4、说明:创建新表 oToUpkAI
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) @%K@oD L
根据已有的表创建新表:
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A:create table tab_new like tab_old (使用旧表创建新表) (AdQ6eGM b
B:create table tab_new as select col1,col2... from tab_old definition only R;f!s/^)
5、说明:删除新表 cSBYC_LU
drop table tabname n8[
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6、说明:增加一个列 'kK}9VKl
Alter table tabname add column col type Y`3>i,S6\
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。 5/Q^p"
7、说明:添加主键: Alter table tabname add primary key(col) <ok/2v
说明:删除主键: Alter table tabname drop primary key(col) b$+.}&M
8、说明:创建索引:create [unique] index idxname on tabname(col....) 0Q=4{*:?
删除索引:drop index idxname A5zT^!`[
注:索引是不可更改的,想更改必须删除重新建。 w Maib3Q
9、说明:创建视图:create view viewname as select statement fNc3&=]]
删除视图:drop view viewname LzS@@']
10、说明:几个简单的基本的sql语句 |jniI(
选择:select * from table1 where 范围 [|\~-6"7N|
插入:insert into table1(field1,field2) values(value1,value2) 8|`4D 'Ln
删除:delete from table1 where 范围 qde.;Yv9
更新:update table1 set field1=value1 where 范围 )G0a72
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! iU\WV
排序:select * from table1 order by field1,field2 [desc] %J?;@ G)r
总数:select count as totalcount from table1 1_!*R]a q
求和:select sum(field1) as sumvalue from table1 :~pPB#)nk
平均:select avg(field1) as avgvalue from table1 pUWj,&t
最大:select max(field1) as maxvalue from table1 Zycu3%JI
最小:select min(field1) as minvalue from table1 SqTO~zGC
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11、说明:几个高级查询运算词 INsc!xOQ
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A: UNION 运算符 iNgHx[*?
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。 XS]=sfN
B: EXCEPT 运算符 *BT-@V.4
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。 =usx' #rb
C: INTERSECT 运算符 r"SuE:D
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。 AW4N#gt8',
注:使用运算词的几个查询结果行必须是一致的。 'c\zWmAZ
12、说明:使用外连接 JB a:))lw
A、left outer join: Aq}]{gfQ1
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。 _mKO4Atw
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 n0kBLn
B:right outer join: -82Rz
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。 q3B#rje>h
C:full outer join: [ottUS@
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。 &)O X*y
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二、提升 j8!fzJG
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) [L8Bgw1
法一:select * into b from a where 1<>1 _K>cB<+d
法二:select top 0 * into b from a 1"009/|
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) cpp0Y^
insert into b(a, b, c) select d,e,f from b; xCD|UC46?X
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) DF/p{s1Y3
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 l)fF)\ |;=
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. a%7ju4CVj
4、说明:子查询(表名1:a 表名2:b) 2:Q9gru
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) WaQCq0Enj
5、说明:显示文章、提交人和最后回复时间 /NaIMo5
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b b&B<'Wb
6、说明:外连接查询(表名1:a 表名2:b) SY_T\
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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 jm'(t=Ze
7、说明:在线视图查询(表名1:a ) s(J,TS#I]
select * from (SELECT a,b,c FROM a) T where t.a > 1; FJgr=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 ZkkXITQkPM
select * from table1 where time between time1 and time2 wX" 6 S:
select a,b,c, from table1 where a not between 数值1 and 数值2 5zX;/n~
9、说明:in 的使用方法 /i$E |[
select * from table1 where a [not] in ('值1','值2','值4','值6') _` |Hk2O
10、说明:两张关联表,删除主表中已经在副表中没有的信息 |AW[4Yn>
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) P*XLm
11、说明:四表联查问题: K_',Gd4L
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 ..... s={AdQ
12、说明:日程安排提前五分钟提醒 hgX@?WWR
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 @dV'v{:,
13、说明:一条sql 语句搞定数据库分页 G eN('0
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 qi_[@da f?
14、说明:前10条记录 wP- pFc
select top 10 * form table1 where 范围 f@T/^|`mh
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.) =O1N*'e
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) E8u:Fgs
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 }9
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(select a from tableA ) except (select a from tableB) except (select a from tableC) \1hbCv$Hf
17、说明:随机取出10条数据 | Uf6k`
select top 10 * from tablename order by newid() sptDzVM
18、说明:随机选择记录 ;(fD R8
select newid() >XjSVRO
19、说明:删除重复记录 h.ojj$f,
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) *fso6j#%
20、说明:列出数据库里所有的表名 (p'yya{(
select name from sysobjects where type='U' |\%[e@u
21、说明:列出表里的所有的 kMAQHpDD
select name from syscolumns where id=object_id('TableName') nVko]y
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。 KlDW'R$
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 r4k=i4
显示结果: X90VJb]
type vender pcs )uiYu3 I
电脑 A 1 o {Sc
电脑 A 1 \:]Clvc
光盘 B 2 {$)zC*l
光盘 A 2 r5> FU>7'
手机 B 3 _?kjIF
手机 C 3 p<*3mbgGO
23、说明:初始化表table1 -gefdx6ES
TRUNCATE TABLE table1 k`U")lv
24、说明:选择从10到15的记录 O7%<(
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc &duWV6Acw
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三、技巧 P%
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1、1=1,1=2的使用,在SQL语句组合时用的较多 :jB~rhZ~
"where 1=1" 是表示选择全部 "where 1=2"全部不选, G
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如: bO>q`%&
if @strWhere !='' trcG^uV
begin :#1{c^i%3
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere z$$ E7i
end >Lx,<sE
else m.e+S,i
begin ]l7) F-v
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' qZACX.Hw
end =<R")D]4z
我们可以直接写成 %yX?4T;b
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 'd 4I/
2、收缩数据库 S.1\e"MfI
--重建索引 [ Hw
DBCC REINDEX rXc-V},az8
DBCC INDEXDEFRAG QE*O~Yj
--收缩数据和日志 16ahU$@-
DBCC SHRINKDB zgRZgVj
DBCC SHRINKFILE =B<>H$
3、压缩数据库 `&2~\o/
dbcc shrinkdatabase(dbname) bD*V$w*P
4、转移数据库给新用户以已存在用户权限 {I0b%>r=
exec sp_change_users_login 'update_one','newname','oldname' +?Vj}p;
go g*?)o!_*
5、检查备份集 S7]\tw_L)
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' EITA[Ba B`
6、修复数据库 H6%QM}t
ALTER DATABASE [dvbbs] SET SINGLE_USER b9Jah
GO 8}z]B^?Fy
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK yH5^EY7rQ
GO ms2y[b
ALTER DATABASE [dvbbs] SET MULTI_USER =&G<^7
GO |b"
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7、日志清除 P,U$
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SET NOCOUNT ON =lY6v-MBw
DECLARE @LogicalFileName sysname, \^a(B{
@MaxMinutes INT, t&}Z~Zp
@NewSize INT "}
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USE tablename -- 要操作的数据库名 V}gP'f07zy
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 JLo'=(
@MaxMinutes = 10, -- Limit on time allowed to wrap log. zmd,uhNc:
@NewSize = 1 -- 你想设定的日志文件的大小(M) )a"rj5~-
-- Setup / initialize .XDY1~w0
DECLARE @OriginalSize int %;ZWYj`]n
SELECT @OriginalSize = size w/_n$hX
FROM sysfiles VQ wr8jXye
WHERE name = @LogicalFileName Cq\1t
SELECT 'Original Size of ' + db_name() + ' LOG is ' + !wP|t#Sc9
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + =OY&;d!C
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' (1pI#H"f9
FROM sysfiles /Iht,@%E
WHERE name = @LogicalFileName \1|]?ZQ\ K
CREATE TABLE DummyTrans 0qP&hybL[(
(DummyColumn char (8000) not null) OiBDI3,|+
DECLARE @Counter INT, RO.GD$ 3n
@StartTime DATETIME, z\64Qpfm
@TruncLog VARCHAR(255) r*?rwtFtg
SELECT @StartTime = GETDATE(), Mx?]7tI
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' y.,S}7l:
DBCC SHRINKFILE (@LogicalFileName, @NewSize) GVS-_KP\
EXEC (@TruncLog) ZccQ{$0H
-- Wrap the log if necessary. Z9Prw/8P
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) .G-F5`2I
AND (@OriginalSize * 8 /1024) > @NewSize s}"5uDfn1F
BEGIN -- Outer loop. T}')QC&wQ
SELECT @Counter = 0 OSP#FjH
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) /8m2oL\<
BEGIN -- update wkNf[>jX?
INSERT DummyTrans VALUES ('Fill Log') @;>i3?
DELETE DummyTrans OS|uZ<"Rq3
SELECT @Counter = @Counter + 1 ybnq;0}$
END kkWqP20q
EXEC (@TruncLog) w&&uk[Gh/a
END S}fU2Wi
SELECT 'Final Size of ' + db_name() + ' LOG is ' + QY14N{]T\p
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + "s-e)svB
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' <3?T^/8
FROM sysfiles Ce&nMgd~
WHERE name = @LogicalFileName _<Hx1l~
DROP TABLE DummyTrans R}~p1=D
SET NOCOUNT OFF 9J>b6
8、说明:更改某个表 fpMnA
exec sp_changeobjectowner 'tablename','dbo' &qR1fbw"
9、存储更改全部表 epz'GN]V
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 85;hs
@OldOwner as NVARCHAR(128), Q
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@NewOwner as NVARCHAR(128) -anLp8G*
AS BPf;!.
DECLARE @Name as NVARCHAR(128) n0nf;E
DECLARE @Owner as NVARCHAR(128) `v2]Jk<
DECLARE @OwnerName as NVARCHAR(128) 4a'O#;ho
DECLARE curObject CURSOR FOR DGfhS` X
select 'Name' = name, ?Q$LIoR
'Owner' = user_name(uid) /48W]a}JS
from sysobjects %cIF()
where user_name(uid)=@OldOwner >y
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order by name 2kv%k3Q{
OPEN curObject D+$ k
FETCH NEXT FROM curObject INTO @Name, @Owner kk`BwRh)d;
WHILE(@@FETCH_STATUS=0) , $;g'z!N
BEGIN /cmnX'z
if @Owner=@OldOwner $^&SEz
begin _W@SCV)yH
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 7lP3\7wD@9
exec sp_changeobjectowner @OwnerName, @NewOwner fwR3=:5~
end ,.#
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-- select @name,@NewOwner,@OldOwner JGmW>mH
FETCH NEXT FROM curObject INTO @Name, @Owner M :m-i X
END `b(y 5 Z
close curObject !8 3x,*O
deallocate curObject >)Ih[0~M
GO Z=;+)
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10、SQL SERVER中直接循环写入数据
Dq T)%a
declare @i int @ mzf(Aq
set @i=1 .3;bUJ1
while @i<30 @G/':N
begin kBPFk t2
insert into test (userid) values(@i) m7:E73:
set @i=@i+1 'WqSHb7
end %}z/_QZ
小记存储过程中经常用到的本周,本月,本年函数 %9_wDfw~
Dateadd(wk,datediff(wk,0,getdate()),-1) jgiP2k[Xom
Dateadd(wk,datediff(wk,0,getdate()),6) v\9:G
Dateadd(mm,datediff(mm,0,getdate()),0) ETu7G5?
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) o?G^=0T
Dateadd(yy,datediff(yy,0,getdate()),0) MSEBvZ-
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) wf7<#jIq
上面的SQL代码只是一个时间段 `[+9n2j
Dateadd(wk,datediff(wk,0,getdate()),-1) vFfvvRda4x
Dateadd(wk,datediff(wk,0,getdate()),6) Z=: oIAe
就是表示本周时间段. JCIm*6~
下面的SQL的条件部分,就是查询时间段在本周范围内的: !g? ~<`
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) -Q@jL{Ue
而在存储过程中 #unE>#DW
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) //--r5Q
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) {$iJYS\