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。 EM([N*8o
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一、基础 9wAP%xh
1、说明:创建数据库 */qv}
CREATE DATABASE database-name +6TKk~0e^
2、说明:删除数据库 5\a5^FK~
drop database dbname %b_zUFHPp
3、说明:备份sql server z24-hC
--- 创建 备份数据的 device LAvAjvRc
USE master _x>u"w
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ciXAyT cG
--- 开始 备份 U3Dy:K[
BACKUP DATABASE pubs TO testBack 3*'!,gK~[
4、说明:创建新表 lc'Jn$O@
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) }LE/{]A
根据已有的表创建新表: 'Y-c*q
A:create table tab_new like tab_old (使用旧表创建新表) 9> (8r+
B:create table tab_new as select col1,col2... from tab_old definition only M2m@N-+R
5、说明:删除新表 4sva%Up
drop table tabname WIbU^WJ0
6、说明:增加一个列 t[DXG2&
Alter table tabname add column col type )X7ZX#ttH
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。 mM95BUB
7、说明:添加主键: Alter table tabname add primary key(col) '7xY,IY
说明:删除主键: Alter table tabname drop primary key(col) .vb*|So
8、说明:创建索引:create [unique] index idxname on tabname(col....) Jl4zj>8~
删除索引:drop index idxname pQqZ4L6v
注:索引是不可更改的,想更改必须删除重新建。 &KD
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9、说明:创建视图:create view viewname as select statement _-h3>.;h9
删除视图:drop view viewname Karyipn}
10、说明:几个简单的基本的sql语句 .+8w\>w6g
选择:select * from table1 where 范围 Cx@, J\rsQ
插入:insert into table1(field1,field2) values(value1,value2) 'DKP-R"
删除:delete from table1 where 范围 Ig=4Z*au!g
更新:update table1 set field1=value1 where 范围 L>PpXTWwy
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! kdF#Nm
排序:select * from table1 order by field1,field2 [desc] `5gcc7b
总数:select count as totalcount from table1 C f<,\Aav
求和:select sum(field1) as sumvalue from table1 T{ojla(
平均:select avg(field1) as avgvalue from table1 ]6(NeS+
最大:select max(field1) as maxvalue from table1 b0
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最小:select min(field1) as minvalue from table1 {0[qERj"z
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11、说明:几个高级查询运算词 W"~G]a+
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A: UNION 运算符 /FQumqbnt
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。 gsZCWT
B: EXCEPT 运算符 2B*9]AHny
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。 ]pFYAe ?
C: INTERSECT 运算符 u9?85
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。 ")8wu1V-
注:使用运算词的几个查询结果行必须是一致的。 _p90Zm-3X
12、说明:使用外连接 d_OHQpfK
A、left outer join: H 7R1GaJ
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。 vZk+NS<
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 pfZxG.l
B:right outer join: +p_SKk!%+
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。 o05) I2
C:full outer join: d F),
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。 gB&'MA!
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二、提升 l3.HL> o
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) A}W&=m8!
法一:select * into b from a where 1<>1 xKIm2% U9
法二:select top 0 * into b from a F*(<`V
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) m 'a3}vRV(
insert into b(a, b, c) select d,e,f from b; TMq\}k-I5
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) [P"#?7 N
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 p>!`JU`{?
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. (m@({
4、说明:子查询(表名1:a 表名2:b) 6Si z9
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) *)"`v]
5、说明:显示文章、提交人和最后回复时间 (LGx;9S?
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b "Z#&A
6、说明:外连接查询(表名1:a 表名2:b) Vw+U?
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c S3.Pqp_<
7、说明:在线视图查询(表名1:a ) ;i\i+:=
select * from (SELECT a,b,c FROM a) T where t.a > 1; w+[r$+z!k
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 I>fEwMk~
select * from table1 where time between time1 and time2 M$|^?U>cm
select a,b,c, from table1 where a not between 数值1 and 数值2 #lF8"@)a-$
9、说明:in 的使用方法 o-49o5:1
select * from table1 where a [not] in ('值1','值2','值4','值6') ?7(`2=J
10、说明:两张关联表,删除主表中已经在副表中没有的信息 m~%IHWO'
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) {PdyKgM
11、说明:四表联查问题: J6=*F;x6E
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 ..... iN=-N=
12、说明:日程安排提前五分钟提醒 N^:)U"9*e
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 }Vk#w%EJ
13、说明:一条sql 语句搞定数据库分页 cO_En`F
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%"v7G-
14、说明:前10条记录 sJMT _yt;
select top 10 * form table1 where 范围 +Z/Pj_.o
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.) Pij*?qmeQ
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) qm]k
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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 tP7l
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(select a from tableA ) except (select a from tableB) except (select a from tableC) IJ[#$I+Z%
17、说明:随机取出10条数据 z[[|'02{
select top 10 * from tablename order by newid() F"~uu9u
18、说明:随机选择记录 O cd
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select newid() pWK7B`t
19、说明:删除重复记录 epR7p^`7
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) v2/@Pu!kg
20、说明:列出数据库里所有的表名 1iig0l6\m
select name from sysobjects where type='U' #r>
21、说明:列出表里的所有的 jl%27Ld
select name from syscolumns where id=object_id('TableName') a%V6RyT4qW
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。 t4~Bn<=
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 P^T]U bv"
显示结果: &n91f
type vender pcs c|IH|y
电脑 A 1 &Z#g/Hc
电脑 A 1 NRgNh5/
光盘 B 2 'z>|N{-xG
光盘 A 2 FK{Vnj0
手机 B 3 ]uG9WT6l
手机 C 3 L;wzvz\+
23、说明:初始化表table1 Jvgx+{Xu
TRUNCATE TABLE table1 Q6]SsV?x
24、说明:选择从10到15的记录 Fzt{^%\`
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc p0>W}+8fF
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三、技巧 'QeCJ5p]
1、1=1,1=2的使用,在SQL语句组合时用的较多 r[ni{&
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ot8UuBq
如: ZvM~]8m
if @strWhere !='' MV'q_{J
begin ..)O/g.
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere aHuZzYQ*"j
end K!=Y4"5%
else 33:{IV;k
begin 6Q"fRXM
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Gx,<|v
end 7A<X!a
我们可以直接写成 "**Tw'
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 4"at~K`
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2、收缩数据库 Py_yIwQqg
--重建索引 p.~hZ+ x_
DBCC REINDEX RoS&oGYqR
DBCC INDEXDEFRAG *6IytWOX5
--收缩数据和日志 Wl\.*^`k
DBCC SHRINKDB o9*}>J<+RQ
DBCC SHRINKFILE +"
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3、压缩数据库 z10J8Ms'
dbcc shrinkdatabase(dbname) 'I^3r~_
4、转移数据库给新用户以已存在用户权限 aQzx^%B1
exec sp_change_users_login 'update_one','newname','oldname' BE>^;` K
go
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5、检查备份集 3k3-Ts
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' d< j+a1&
6、修复数据库 }Vjg>"
ALTER DATABASE [dvbbs] SET SINGLE_USER =r:(ga
GO HQGn[7JW
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK A6eIf
GO O*jTrZ(k
ALTER DATABASE [dvbbs] SET MULTI_USER gc,%A'OR^<
GO h9-^aB$8^
7、日志清除 wIeF(}VM
SET NOCOUNT ON ktF\f[
DECLARE @LogicalFileName sysname, vLCyT=OB`
@MaxMinutes INT, C%&A9(jG
@NewSize INT wGy`0c]v?
USE tablename -- 要操作的数据库名 w5Lev}Rb
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 2 8>
@MaxMinutes = 10, -- Limit on time allowed to wrap log. uC$!|I
@NewSize = 1 -- 你想设定的日志文件的大小(M) lZ gX{
-- Setup / initialize ^hZZ5(</8P
DECLARE @OriginalSize int weX%S?
SELECT @OriginalSize = size _?~EWT
FROM sysfiles F)K&a
WHERE name = @LogicalFileName ^jhc(ZW"
SELECT 'Original Size of ' + db_name() + ' LOG is ' + GW{e"b/x
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + g&&-
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' `O,^oD4
FROM sysfiles ?$$Xg3w_#
WHERE name = @LogicalFileName `s8*n(\h
CREATE TABLE DummyTrans K4U_sCh#f
(DummyColumn char (8000) not null) b,h@.s
DECLARE @Counter INT, T&'p5h=l
@StartTime DATETIME, @qUgp*+{
@TruncLog VARCHAR(255) ~ p~
SELECT @StartTime = GETDATE(), '<=77yDg
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' )>"|<h.2]
DBCC SHRINKFILE (@LogicalFileName, @NewSize) tW-wO[2
EXEC (@TruncLog) -8zdkm8k
-- Wrap the log if necessary. tEuVn5
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired uE &/:+
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Y'
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{
AND (@OriginalSize * 8 /1024) > @NewSize zy'e|92aO
BEGIN -- Outer loop. E5iNuJj=f
SELECT @Counter = 0 -sqd?L.p
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) .o#A(3&n
BEGIN -- update _|jEuif
INSERT DummyTrans VALUES ('Fill Log') ZX0#I W
DELETE DummyTrans I_k/lwBD
SELECT @Counter = @Counter + 1 dp}s]`x+
END )gVz?-u+D
EXEC (@TruncLog) GAP,$xAaW
END mE"(d*fe'
SELECT 'Final Size of ' + db_name() + ' LOG is ' + E[NszM[P
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + *q-VY[2
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' >q&X#E<w
FROM sysfiles #W9{3JGUY
WHERE name = @LogicalFileName !-HJ%(5:F
DROP TABLE DummyTrans `;Od0uh
SET NOCOUNT OFF :lU#Dm]
8、说明:更改某个表 "W^+NeLc
exec sp_changeobjectowner 'tablename','dbo' w!_6*
9、存储更改全部表 ;UpdkY
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch vJj}$AlI
@OldOwner as NVARCHAR(128), <s=i5t
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@NewOwner as NVARCHAR(128) 6w`.'5
AS ]!>tP,<`'
DECLARE @Name as NVARCHAR(128) Suo%uD
DECLARE @Owner as NVARCHAR(128) U6?3 z
DECLARE @OwnerName as NVARCHAR(128) `T,^os#6
DECLARE curObject CURSOR FOR .k -!/ ^
select 'Name' = name, GLp~SeF#
'Owner' = user_name(uid) w,*#z
from sysobjects )vD:
where user_name(uid)=@OldOwner ]P*H,&I`#
order by name f
= 'AI
OPEN curObject hG2WxYk
FETCH NEXT FROM curObject INTO @Name, @Owner V}h
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WHILE(@@FETCH_STATUS=0) mrQT:B\8
BEGIN L[voouaqm
if @Owner=@OldOwner \MDhm,H<
begin K%.t%)A_3
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ^U9b)KA
exec sp_changeobjectowner @OwnerName, @NewOwner SuA
@S
end "cwvx8un
-- select @name,@NewOwner,@OldOwner f"-3'kqo
FETCH NEXT FROM curObject INTO @Name, @Owner kx%\Cz
END o&$Of
close curObject 6 \?GY
deallocate curObject V'FKgzd
GO #Xk/<It
10、SQL SERVER中直接循环写入数据 .6c
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declare @i int OIs!,G|
set @i=1 U!jRF
while @i<30 eIj2(q9
begin ]+5Y\~I
insert into test (userid) values(@i) l0PXU)>C
set @i=@i+1
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end q*<FfO=eQ
小记存储过程中经常用到的本周,本月,本年函数 T"DG$R,Aj
Dateadd(wk,datediff(wk,0,getdate()),-1) $\#wsI(
Dateadd(wk,datediff(wk,0,getdate()),6) p4uN+D`.U
Dateadd(mm,datediff(mm,0,getdate()),0) DfjDw/{U3L
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) NC3XJ
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Dateadd(yy,datediff(yy,0,getdate()),0) JMfv|>=
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 0HI0/Tvu$<
上面的SQL代码只是一个时间段 RF
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Dateadd(wk,datediff(wk,0,getdate()),-1) [dy0aR$>d
Dateadd(wk,datediff(wk,0,getdate()),6) t(99m=9>
就是表示本周时间段. 19bqz )
下面的SQL的条件部分,就是查询时间段在本周范围内的: b y$S#ef
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) qFp]jbU
而在存储过程中 GPrq(
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) E~S~Ld%
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 2;7n0LOs}