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。 `g_r<EY8/
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一、基础 >=d 5Scix
1、说明:创建数据库 !PA ><F
CREATE DATABASE database-name '`YZJ
2、说明:删除数据库 K_AdMXF9
drop database dbname UlWm).
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3、说明:备份sql server o[1#)&
--- 创建 备份数据的 device +!GJ
USE master ^D1gcI
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' }$'XV.
--- 开始 备份 GKbbwT0T|
BACKUP DATABASE pubs TO testBack ]61Si~Z
4、说明:创建新表 #sg*GK+|:R
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Yi]`"\
根据已有的表创建新表: 5A$,'%d
A:create table tab_new like tab_old (使用旧表创建新表) OTGy[jY"
B:create table tab_new as select col1,col2... from tab_old definition only t-5K
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5、说明:删除新表 /k[8xb
drop table tabname ?S'aA!/;
6、说明:增加一个列 l[]cUE
Alter table tabname add column col type %-]a[qf3
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。 +?W4ac1
7、说明:添加主键: Alter table tabname add primary key(col) +0 }_X
说明:删除主键: Alter table tabname drop primary key(col) [!>9K}z,=
8、说明:创建索引:create [unique] index idxname on tabname(col....) f ~*7hv\
删除索引:drop index idxname `dD_"Hdt
注:索引是不可更改的,想更改必须删除重新建。 '=O1n H<
9、说明:创建视图:create view viewname as select statement 8{]nS8i
删除视图:drop view viewname @ze2'56F}
10、说明:几个简单的基本的sql语句 Q lA?dXQ
选择:select * from table1 where 范围 @)x*6 2r+
插入:insert into table1(field1,field2) values(value1,value2) ,a?oGi
删除:delete from table1 where 范围 3;FV^V'
更新:update table1 set field1=value1 where 范围 5]GgjQ
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! -Bl^TT
排序:select * from table1 order by field1,field2 [desc] BsA'r+ho?H
总数:select count as totalcount from table1 7AS_Aw1L
求和:select sum(field1) as sumvalue from table1 :\I*_00!
平均:select avg(field1) as avgvalue from table1 ?:M4GY"gV
最大:select max(field1) as maxvalue from table1 ML MetRP
最小:select min(field1) as minvalue from table1 o
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11、说明:几个高级查询运算词 NjT*5 .
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A: UNION 运算符 O) TS$
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。 )[cuYH>
B: EXCEPT 运算符 K3<A<&W_-
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。 ;BqCjS%`N
C: INTERSECT 运算符 n((A: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。 6D[]Jf,9
注:使用运算词的几个查询结果行必须是一致的。 }vh4ix
12、说明:使用外连接 q*4U2_^.
A、left outer join: \{]y(GT
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。 (5E09K$
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 Ue60Mf
B:right outer join: ;2\6U;
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。 W8$0y2
C:full outer join: "/RMIS
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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。 JBLUX,
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二、提升 Rzh.zvxTp
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) m(?{#aaq
法一:select * into b from a where 1<>1 b1cVAfUP
法二:select top 0 * into b from a <ShA_+Nd
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) i7 21(1
insert into b(a, b, c) select d,e,f from b; $i6z)]rjg
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) G'p322Bu
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 T)OR HJ&,
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. xpO;V}M|
4、说明:子查询(表名1:a 表名2:b) .4 U*.Rf
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) n}[S
5、说明:显示文章、提交人和最后回复时间 ;1PJS_@rX
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b j)Ak:l%a
6、说明:外连接查询(表名1:a 表名2:b) JKfJ%yy |
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c !H)-
7、说明:在线视图查询(表名1:a ) rm9>gKN;#
select * from (SELECT a,b,c FROM a) T where t.a > 1; cV0CI&
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 ,c^nW
select * from table1 where time between time1 and time2 "OK[uug
select a,b,c, from table1 where a not between 数值1 and 数值2 ?>7-a~*A@
9、说明:in 的使用方法 a*LfT<hmU3
select * from table1 where a [not] in ('值1','值2','值4','值6') 0+ $gR~^^
10、说明:两张关联表,删除主表中已经在副表中没有的信息 #T2J +
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 1%*\*z
11、说明:四表联查问题: 7(X
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select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... GM'yOJo
12、说明:日程安排提前五分钟提醒 '7PaJj=Nx
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 G" E_4YkJ
13、说明:一条sql 语句搞定数据库分页 s[y.gR.(
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 !&hqj$>-}
14、说明:前10条记录
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select top 10 * form table1 where 范围 ~Ck OiWC0
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.) {ri={p]l
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) jLt3jN
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 Fz,jnV9=j
(select a from tableA ) except (select a from tableB) except (select a from tableC) +)WU:aKI
17、说明:随机取出10条数据 JffaT_"\
select top 10 * from tablename order by newid() {4,],0bjx/
18、说明:随机选择记录 -,b+tC<V)0
select newid() =#[oi3k
19、说明:删除重复记录 ;m#4Q6k)V?
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) V`#2jDz
20、说明:列出数据库里所有的表名 q)Nw$dW<
select name from sysobjects where type='U' b^C27s
21、说明:列出表里的所有的 Ze8.+Ee
select name from syscolumns where id=object_id('TableName') x51R:x(p
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 oPr`SYB
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type t1o
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显示结果: j|wN7@Zc
type vender pcs [8IO0lul+
电脑 A 1 9QLG:(~;
电脑 A 1 d[p2?]
光盘 B 2 <>9!oOa
光盘 A 2 (^y"'B
手机 B 3 OVDuF&0
手机 C 3 `MuX/[q
23、说明:初始化表table1 65qqs|&w;[
TRUNCATE TABLE table1 _Iav2=0Wi
24、说明:选择从10到15的记录 >FwK_Zd'
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc |r Aot2
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三、技巧 7]zZdqG&p`
1、1=1,1=2的使用,在SQL语句组合时用的较多 {~&Q"8
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, {~ F|"v
如: "4H@&:-(p
if @strWhere !='' :R=6Ku>
begin <6Gs0\JB
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere >h;]rMD!|
end :tU^
else X:g5;NT
begin GIxs>E'X
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 0LH6G[
end wCNn/%C
我们可以直接写成 I
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere *YeQCt-l
2、收缩数据库 ;Go^)bN
;
--重建索引 S\8v)|Pr
DBCC REINDEX pN5kcvQ
DBCC INDEXDEFRAG HS{Vohy >
--收缩数据和日志 N=<`|I
DBCC SHRINKDB CL1*pL
DBCC SHRINKFILE |*NZ^6`@
3、压缩数据库 Mc asnjC
dbcc shrinkdatabase(dbname) b-VygLN
4、转移数据库给新用户以已存在用户权限 +|obU9M
exec sp_change_users_login 'update_one','newname','oldname' e!jy6t
go =b:XL#VA
5、检查备份集 EwN{| 34C
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ^_Hf}8H7]
6、修复数据库 G5/A{1sz&
ALTER DATABASE [dvbbs] SET SINGLE_USER 2@6@|jRG
GO `_OrBu[
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 8A3/@Z;0S
GO ^BA%]pe$I
ALTER DATABASE [dvbbs] SET MULTI_USER `/>kN%
GO ylZQwICk
7、日志清除 >pfeP"[(3
SET NOCOUNT ON J@I>m N1\
DECLARE @LogicalFileName sysname, F&czD;F
@MaxMinutes INT, :IS?si5|
@NewSize INT p lnH
USE tablename -- 要操作的数据库名 /_qq(,3
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 5N|LT8P}Z
@MaxMinutes = 10, -- Limit on time allowed to wrap log. <N= k&\
@NewSize = 1 -- 你想设定的日志文件的大小(M) ,7&\jET5^0
-- Setup / initialize (V6bX]<
DECLARE @OriginalSize int I!Z`'1"
SELECT @OriginalSize = size 3tTOs
FROM sysfiles z:#]P0
WHERE name = @LogicalFileName CLaQE{
SELECT 'Original Size of ' + db_name() + ' LOG is ' + .u&xo{$'dS
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + (O0 Ry2uk
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' |z=`Ur@)
FROM sysfiles ct3i^,i
WHERE name = @LogicalFileName AuXUD9-
CREATE TABLE DummyTrans z.cDbkf}
(DummyColumn char (8000) not null) H 1kI+YJ@
DECLARE @Counter INT, B&a{,.m&q6
@StartTime DATETIME, FFcCoPX_
@TruncLog VARCHAR(255) Z2$_9.
SELECT @StartTime = GETDATE(),
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' hD
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) d,(y$V+
EXEC (@TruncLog) CwX?%$S
-- Wrap the log if necessary. G)?*BH
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired J.1c,@
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) R
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AND (@OriginalSize * 8 /1024) > @NewSize \yJ
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BEGIN -- Outer loop. DPzW,aIgv
SELECT @Counter = 0 )sm9%|.&
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) hc|A:v)]
BEGIN -- update NlEyT9
INSERT DummyTrans VALUES ('Fill Log') ~{Iw[,MJ
DELETE DummyTrans ZR}v_]l^
SELECT @Counter = @Counter + 1 eA!Z7 '
END .A< HM}
EXEC (@TruncLog) Og7yT{h_
END =IMmtOvJ
SELECT 'Final Size of ' + db_name() + ' LOG is ' + _h-agn4[i
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 3<r7"/5
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ,IPt4EH$
FROM sysfiles A`3KE9ED
WHERE name = @LogicalFileName '0+I' _(
DROP TABLE DummyTrans ZwMVFC-d
SET NOCOUNT OFF d*^JO4'
8、说明:更改某个表 !
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exec sp_changeobjectowner 'tablename','dbo' ':4<[Vk
9、存储更改全部表 >j=ZB3yZ
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch U7g`R@
@OldOwner as NVARCHAR(128), $#hU_vr
@NewOwner as NVARCHAR(128) E'f7=ChNF
AS &gXL{cK'%
DECLARE @Name as NVARCHAR(128) %1A8m-u]M
DECLARE @Owner as NVARCHAR(128) 89&9VX^A
DECLARE @OwnerName as NVARCHAR(128) C|&tdh :g
DECLARE curObject CURSOR FOR }+ KM"+@$<
select 'Name' = name, u;q
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'Owner' = user_name(uid) B46:LQ9[
from sysobjects n>v1<^
where user_name(uid)=@OldOwner *LB-V%{|'
order by name bPOPoq1#
OPEN curObject e#;43=/Ia
FETCH NEXT FROM curObject INTO @Name, @Owner "rn
WHILE(@@FETCH_STATUS=0) Z3TCi7,m
BEGIN ?_gvI
if @Owner=@OldOwner &s`)_P[
begin bPFGQlmIO
set @OwnerName = @OldOwner + '.' + rtrim(@Name) B9"o Ru^}
exec sp_changeobjectowner @OwnerName, @NewOwner HKJCiQ|k
end ;I*t5{
-- select @name,@NewOwner,@OldOwner kc2B_+Y1
FETCH NEXT FROM curObject INTO @Name, @Owner t08U9`w
END MM32\}Y6
close curObject :5~Dca_iU4
deallocate curObject 1/9*c *w
GO N9/k`ZGC
10、SQL SERVER中直接循环写入数据 F7=9> ,
declare @i int gV@xu)l
set @i=1 aftt^h
while @i<30 \;0pjxq=
begin F\JS?zt2
insert into test (userid) values(@i) %DiQTg7V,
set @i=@i+1 i
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end AJ/Hw>>$?m
小记存储过程中经常用到的本周,本月,本年函数 4xW~@meNB
Dateadd(wk,datediff(wk,0,getdate()),-1) 2`]c&k;]
Dateadd(wk,datediff(wk,0,getdate()),6) %.$!VTO"
Dateadd(mm,datediff(mm,0,getdate()),0) uY~mi9E
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) /9ORVV
Dateadd(yy,datediff(yy,0,getdate()),0) l5w^rj
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) F[\T'{
上面的SQL代码只是一个时间段 t_Eivm-,B
Dateadd(wk,datediff(wk,0,getdate()),-1) js"Yh
Dateadd(wk,datediff(wk,0,getdate()),6) J0IKI,X.
就是表示本周时间段. _W(xO
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下面的SQL的条件部分,就是查询时间段在本周范围内的: R WY>`.su
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Bdh*[S\u@E
而在存储过程中 -4QZ/ *
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) LkJq Bg
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 85#
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