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。 J.JD8o9sa
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一、基础 q>(?Z#sB
1、说明:创建数据库 lt-3OcC
CREATE DATABASE database-name )&T 5/+
2、说明:删除数据库 FDgo6x
drop database dbname t#(=$
3、说明:备份sql server m
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--- 创建 备份数据的 device EHq;eF
USE master e'uC:O.u
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' )w4U]inJ$"
--- 开始 备份 KH)-=IJ8
BACKUP DATABASE pubs TO testBack ?ja%*0
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4、说明:创建新表 o*A, 6y
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) gd
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根据已有的表创建新表: lZRO"[<
A:create table tab_new like tab_old (使用旧表创建新表) 3U^Vz9LW
B:create table tab_new as select col1,col2... from tab_old definition only j~Pwt9G
5、说明:删除新表 [<,7LG<
drop table tabname DX! dU'tj
6、说明:增加一个列 FbuWFC
Alter table tabname add column col type <5%*"v
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 0V-jOc
7、说明:添加主键: Alter table tabname add primary key(col) odca?
说明:删除主键: Alter table tabname drop primary key(col) Ud+,/pE>FA
8、说明:创建索引:create [unique] index idxname on tabname(col....) /1Gmga5
删除索引:drop index idxname #W8F_/!n|
注:索引是不可更改的,想更改必须删除重新建。 c/88|k
9、说明:创建视图:create view viewname as select statement JYj*.Q0
删除视图:drop view viewname w/
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10、说明:几个简单的基本的sql语句 ;+C$EJw-
选择:select * from table1 where 范围 GXm#\)
插入:insert into table1(field1,field2) values(value1,value2) >"IG\//I
删除:delete from table1 where 范围 ym5@SBqIx
更新:update table1 set field1=value1 where 范围 ASov/<D_q
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 0p[k7W u
排序:select * from table1 order by field1,field2 [desc] ,sSo\%
总数:select count as totalcount from table1 w tGS"L
求和:select sum(field1) as sumvalue from table1 g%=K
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平均:select avg(field1) as avgvalue from table1 ?,7!kTRH
最大:select max(field1) as maxvalue from table1 &I=o1F2B)
最小:select min(field1) as minvalue from table1 i/*)1;xsk
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11、说明:几个高级查询运算词 HqsqUS3[
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A: UNION 运算符
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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。 h8O\sKn
B: EXCEPT 运算符 u(3 uZ:
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。 XK\nOHLS
C: INTERSECT 运算符 !pU^?Hy=
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。 l[_antokn
注:使用运算词的几个查询结果行必须是一致的。 >Z*b0j
12、说明:使用外连接 ZDaHR-%Y
A、left outer join: d)U(XiK'
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。 | eCVq(R
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 UTE6U6
B:right outer join: 4jDi3MMU9
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。 yw:%)b{
C:full outer join: xU%]G.k
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。 6<@+J
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二、提升 {hN\=_6*EW
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) m4h)Wq
法一:select * into b from a where 1<>1 An#[
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法二:select top 0 * into b from a Y?1T
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ZzBaYoNy[0
insert into b(a, b, c) select d,e,f from b; +}at#%1@
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) _;^x^
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 v+x rnz
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. $X;OK
4、说明:子查询(表名1:a 表名2:b) vh&~Y].W Y
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) p@q20>^u
5、说明:显示文章、提交人和最后回复时间 5N>f lQ
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b \C~6
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6、说明:外连接查询(表名1:a 表名2:b) c}$>UhLe
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{o,*QL
7、说明:在线视图查询(表名1:a ) `+(n+QS _
select * from (SELECT a,b,c FROM a) T where t.a > 1; bxPa|s?
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 {q$U\y%Rq
select * from table1 where time between time1 and time2 w5y.kc;
select a,b,c, from table1 where a not between 数值1 and 数值2 e8):'Cb
9、说明:in 的使用方法 J
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select * from table1 where a [not] in ('值1','值2','值4','值6') 8IL5:7H8
10、说明:两张关联表,删除主表中已经在副表中没有的信息 v
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) <(TAA15Xol
11、说明:四表联查问题: Ep;?%o ,G
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... jTqJ(M}L
12、说明:日程安排提前五分钟提醒 indbg
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 @I1*b>X~<
13、说明:一条sql 语句搞定数据库分页 b(mZ/2,B
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 < ~CY?
14、说明:前10条记录 Ff0V6j)ji
select top 10 * form table1 where 范围 K)x6F15r
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) nm\f$K>Pg
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) q("l?'
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 Am3j:|>*
(select a from tableA ) except (select a from tableB) except (select a from tableC) rZ.=Lq
17、说明:随机取出10条数据 g,*fpk
select top 10 * from tablename order by newid() + W1l9n*
18、说明:随机选择记录 dk1q9Tx
select newid() d<
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19、说明:删除重复记录 .$d:c61X
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) +KExK2=
20、说明:列出数据库里所有的表名 `lm '_~=`&
select name from sysobjects where type='U' Y:+:>[F
21、说明:列出表里的所有的 %r6_['T
select name from syscolumns where id=object_id('TableName') D->E& #
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。 fh_:ung
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 H/[(T%]o
显示结果: o6 NmDv5
type vender pcs N1g;e?T':
电脑 A 1 k}kwr[
电脑 A 1 wp8-(E^
光盘 B 2 VIGLl'8p
光盘 A 2 =&-.] |t
手机 B 3 aVVE2:M
手机 C 3 gjK: a@{
23、说明:初始化表table1
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TRUNCATE TABLE table1 s$9ow<oi]
24、说明:选择从10到15的记录 sX>|Y3S\U
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc g&B7Y|Es
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三、技巧 O*/Utl
1、1=1,1=2的使用,在SQL语句组合时用的较多 V^D1:9i
"where 1=1" 是表示选择全部 "where 1=2"全部不选,
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如: uVZm9Sp
if @strWhere !='' Y8s-cc(
begin j;Lp@~M
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 26zif
end `ALQSo~l
else 23;\l
begin Nt<Ac&6
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' h9c7P@29
end S)2 U oj
我们可以直接写成 -jTK3&5
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere \n#l+R23
2、收缩数据库 [daR)C
--重建索引 *0a7H$iQ(]
DBCC REINDEX
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DBCC INDEXDEFRAG }LIf]YK
--收缩数据和日志 1U~'8=-
DBCC SHRINKDB 2qj0iRH#N<
DBCC SHRINKFILE ^=cXL
3、压缩数据库 /xA`VyHO
dbcc shrinkdatabase(dbname) h*[sV
4、转移数据库给新用户以已存在用户权限 W89J]#v)k
exec sp_change_users_login 'update_one','newname','oldname' .d)H2X
go wE <PXBl\b
5、检查备份集 M@.?l=1X
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' :e_yOT}}
6、修复数据库 lQ.3_{"s
ALTER DATABASE [dvbbs] SET SINGLE_USER /KJWo0zo
GO Tc;BE
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 9fSX=PVRmQ
GO uTrGb:^
ALTER DATABASE [dvbbs] SET MULTI_USER rPW9lG
GO cz>`$Zz
7、日志清除 "Jyb?5
SET NOCOUNT ON 7.^1I7O
DECLARE @LogicalFileName sysname, <l9qhqHv&
@MaxMinutes INT, =)6|lz^
@NewSize INT BxxqzN+
USE tablename -- 要操作的数据库名 8=sMmpB 7u
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 g'eJN
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 4~:D7",Jn
@NewSize = 1 -- 你想设定的日志文件的大小(M) s.}:!fBk
-- Setup / initialize {-5b[m(
DECLARE @OriginalSize int Zf\It<zT5
SELECT @OriginalSize = size a)L=+Z
FROM sysfiles yF&?gPh&
WHERE name = @LogicalFileName f%d
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + 2-wvL&pi)
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + l]e7
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' !jJH}o/KW
FROM sysfiles fAR0GOI
WHERE name = @LogicalFileName TlBu3z'P
CREATE TABLE DummyTrans z1~U#
(DummyColumn char (8000) not null) F>3fP
DECLARE @Counter INT, ;%i.@@:IQ
@StartTime DATETIME, xF9PjnWF=
@TruncLog VARCHAR(255) $0E_4#kwB
SELECT @StartTime = GETDATE(), 1T7;=<g`
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' fNi_C"<
DBCC SHRINKFILE (@LogicalFileName, @NewSize) K*
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EXEC (@TruncLog) m4T`Tg#P
-- Wrap the log if necessary. nr9cG/"
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired k{$Mlt?&-
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) w~9=6|_
AND (@OriginalSize * 8 /1024) > @NewSize {I_I$x_
BEGIN -- Outer loop. m`ab5<%Gn
SELECT @Counter = 0 (V~PYf%
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) {?'c|\n Li
BEGIN -- update !g-19at
INSERT DummyTrans VALUES ('Fill Log') X=OJgyO/
DELETE DummyTrans aib)ItNb
SELECT @Counter = @Counter + 1 )/<\|mR
END B,dKpz;kFg
EXEC (@TruncLog) ODqWXw#
END 6JL:p{RLi
SELECT 'Final Size of ' + db_name() + ' LOG is ' + v:]
AS:
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + K_~SJbl
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' [R[Suf
FROM sysfiles F{aM6I
WHERE name = @LogicalFileName $lrq*Nf9c
DROP TABLE DummyTrans 'roZ:NE
SET NOCOUNT OFF E
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8、说明:更改某个表 76*5/J-
exec sp_changeobjectowner 'tablename','dbo' ~v<,6BS<$Z
9、存储更改全部表 u
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ^t\AB)(8
@OldOwner as NVARCHAR(128), rRZ ,X%
@NewOwner as NVARCHAR(128) sh"\ kk9
AS 7e-l`]
DECLARE @Name as NVARCHAR(128) KuO5`
DECLARE @Owner as NVARCHAR(128) mM7S9^<UH
DECLARE @OwnerName as NVARCHAR(128) !M&B=vk4
DECLARE curObject CURSOR FOR FVcooV
select 'Name' = name, 3$`qy|=zO
'Owner' = user_name(uid) M e
from sysobjects G?6[K&w
where user_name(uid)=@OldOwner pYs"Y;%
order by name L$+ap~ld
OPEN curObject [0e}%!%M
FETCH NEXT FROM curObject INTO @Name, @Owner VXAgp6
WHILE(@@FETCH_STATUS=0) az]S&\i7T
BEGIN =' cr@[~i
if @Owner=@OldOwner 4RqOg1
begin DNaU
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) 7L:$Amb_F
exec sp_changeobjectowner @OwnerName, @NewOwner ;-d :!*
end M-df Gk
-- select @name,@NewOwner,@OldOwner 6!n%SUt
FETCH NEXT FROM curObject INTO @Name, @Owner b1;80P/:D
END ^4yFLqrC
close curObject GZ];U]_
deallocate curObject [Hww3+~+
GO 7Jm9,4]
10、SQL SERVER中直接循环写入数据 BI] %$rq
declare @i int eS
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set @i=1 *lIK?" mo
while @i<30 `_'I 9,.a
begin d(L u|/~
insert into test (userid) values(@i) { LJRdV
set @i=@i+1 ZIx,?E+eJ
end l~M86 h
小记存储过程中经常用到的本周,本月,本年函数 bgm$<