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。 t,as{.H{h
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一、基础 0OoO cc
1、说明:创建数据库 DG%%]
CREATE DATABASE database-name 2ucsTh@
2、说明:删除数据库 APOU&Wd
drop database dbname \Q
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3、说明:备份sql server g{f>jd
--- 创建 备份数据的 device 6d?2{_} ,
USE master Z6
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' qS`|=5f
--- 开始 备份 `0i}}Zo
BACKUP DATABASE pubs TO testBack oew]ijnB
4、说明:创建新表 "vHAp55B{
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) W YqL
根据已有的表创建新表: 3[g++B."pC
A:create table tab_new like tab_old (使用旧表创建新表) 3Tte8]0
B:create table tab_new as select col1,col2... from tab_old definition only f;;
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5、说明:删除新表 P+c Fp7nC
drop table tabname r:\ 5/0(
6、说明:增加一个列 )*AA9
Alter table tabname add column col type x;b+gIz*
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。 f4 ;8?
7、说明:添加主键: Alter table tabname add primary key(col) 7XI4=O};&%
说明:删除主键: Alter table tabname drop primary key(col) 5@r Zm4U
8、说明:创建索引:create [unique] index idxname on tabname(col....) fbbl92p
删除索引:drop index idxname i)^ZH#Gp
注:索引是不可更改的,想更改必须删除重新建。 |
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9、说明:创建视图:create view viewname as select statement Bv|9{:1%X}
删除视图:drop view viewname -JW6@L@
10、说明:几个简单的基本的sql语句 .j$bCKXGx
选择:select * from table1 where 范围 M:q;z(
插入:insert into table1(field1,field2) values(value1,value2) ""KN?qh9
删除:delete from table1 where 范围 Xcpm?aTo
更新:update table1 set field1=value1 where 范围 }(7QJk5 j
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 2\8\D^
排序:select * from table1 order by field1,field2 [desc] g|*eN{g]uE
总数:select count as totalcount from table1 C36.UZoc
求和:select sum(field1) as sumvalue from table1 1H@rNam&
平均:select avg(field1) as avgvalue from table1 |~vQ0D
最大:select max(field1) as maxvalue from table1 >^)5N<t?
最小:select min(field1) as minvalue from table1 8QgL7
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11、说明:几个高级查询运算词 (6y3"cbe
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A: UNION 运算符 Xv(9 YhS
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 X!+ a;wr
B: EXCEPT 运算符 uz2s- ,
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 v/6,eIz
C: INTERSECT 运算符 WHk/mAI-s
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 D{d$L9.
注:使用运算词的几个查询结果行必须是一致的。 COJ!b
12、说明:使用外连接 6G})h!
A、left outer join: x;]{ 8#-z
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。 0\<-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 ZUI\0qh+
B:right outer join: QKkr~?sTO
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。 p?NjxQLA
C:full outer join: lTd2~_
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。 JF\viMfR
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二、提升 5WN Z7cO
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) PKs%-Uk
法一:select * into b from a where 1<>1 e{+{,g{iu
法二:select top 0 * into b from a hCoLj6Vx
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) M HB]'
insert into b(a, b, c) select d,e,f from b; qxr&_r
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) `ha:Gf
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ,5"]K'Vce
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. #\["y%;W
4、说明:子查询(表名1:a 表名2:b) UN 4)>\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) y$No o)Z
5、说明:显示文章、提交人和最后回复时间 QYb?;Z
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b e%Xf*64
6、说明:外连接查询(表名1:a 表名2:b) 1iW9?=a"
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ymCIk/\
7、说明:在线视图查询(表名1:a ) ~J{{n_G{
select * from (SELECT a,b,c FROM a) T where t.a > 1; H?^#zj`Ex+
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 ~ b_gwJ'
select * from table1 where time between time1 and time2 #iDFGkK/
select a,b,c, from table1 where a not between 数值1 and 数值2 ! HC<aWb
9、说明:in 的使用方法 BT#g?=n#`
select * from table1 where a [not] in ('值1','值2','值4','值6') }f'1x%RS^
10、说明:两张关联表,删除主表中已经在副表中没有的信息 j}*+-.YF
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) JB_`lefW,'
11、说明:四表联查问题: @h,$&=HY
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 ..... ~8{3Fc 0
12、说明:日程安排提前五分钟提醒 bD-Em#>
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 <\EfG:e
13、说明:一条sql 语句搞定数据库分页 GLF"`M /g
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 <%7
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14、说明:前10条记录 cTTE]ix]
select top 10 * form table1 where 范围 j'x{j %U
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.) >7q,[:(gs
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) gD=5M\
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 K7VG\Ec
(select a from tableA ) except (select a from tableB) except (select a from tableC) V gk,+l!4
17、说明:随机取出10条数据 cN>i3}fq
select top 10 * from tablename order by newid() =Q/>g6
18、说明:随机选择记录 m3-J0D<
select newid() _=x_"rzx
19、说明:删除重复记录 xB+H7Ya
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) eF1%5;" W
20、说明:列出数据库里所有的表名 XOU$3+8q5
select name from sysobjects where type='U' ]w_)Spo.
21、说明:列出表里的所有的 c/U6K
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select name from syscolumns where id=object_id('TableName') @v=q,A8_
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。 =1[g`b
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 VrxH6 Y
显示结果: BAHx7x#(
type vender pcs ~mU_`o
电脑 A 1 kR(=VM JU
电脑 A 1 2f4c;YS
光盘 B 2 lHqx}n@e
光盘 A 2 74(J7
手机 B 3 (*BW/.Fq
手机 C 3 =7,UqMl_
23、说明:初始化表table1 @/FX7O{n:
TRUNCATE TABLE table1 1U7HS2
24、说明:选择从10到15的记录 H\bIO!vb
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ~ }22 Dvo
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三、技巧 2GzpWV(
1、1=1,1=2的使用,在SQL语句组合时用的较多 AMz=HN
"where 1=1" 是表示选择全部 "where 1=2"全部不选, R!G7;m'N1
如: Yk?q7xuT
if @strWhere !='' D .`\ ^a
begin <DS6-y
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere N2e<Y_T
end ]S geZ07
else @~3c;9LkY
begin 3wl>a#f
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' i@L2W>{P
end /)TEx}wk
我们可以直接写成 [+z:^a1?V
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere E
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2、收缩数据库 V p{5Kxq
--重建索引 ZRfa!9vl
DBCC REINDEX s3 $Q_8H
DBCC INDEXDEFRAG 3)SZVME1Z
--收缩数据和日志 Q$j48,e
DBCC SHRINKDB ;$< ek(i7
DBCC SHRINKFILE ^ni_%`Ag
3、压缩数据库 4N j?UDa
dbcc shrinkdatabase(dbname) hh&y2#Io
4、转移数据库给新用户以已存在用户权限 5zOSb$;
exec sp_change_users_login 'update_one','newname','oldname' W<o0Z OO
go qH"a !
5、检查备份集 -+|[0hpw
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' n`xh/vGm#
6、修复数据库 E2D8s=r
ALTER DATABASE [dvbbs] SET SINGLE_USER 6QQ oHYtZ
GO <vDm(-i3
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK p ]=;t"
GO w}q"y+=Z:
ALTER DATABASE [dvbbs] SET MULTI_USER pSFWNWQ'B
GO caht4N{T
7、日志清除 U$uO%:4%
SET NOCOUNT ON @x
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DECLARE @LogicalFileName sysname, <Q)}
@MaxMinutes INT, F-0PmO~3+W
@NewSize INT or`stBx
USE tablename -- 要操作的数据库名 |'_<(z
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 [rU8
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. i]pG}SJ
@NewSize = 1 -- 你想设定的日志文件的大小(M) "~
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-- Setup / initialize @un
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DECLARE @OriginalSize int +to9].O7y
SELECT @OriginalSize = size 8 GN{*Hg
FROM sysfiles F9r*ZyNlx
WHERE name = @LogicalFileName c\MDOD%9
SELECT 'Original Size of ' + db_name() + ' LOG is ' + \-w s[
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 1H7Q[ 2E
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Dj"=kL0
FROM sysfiles IxBO$2
WHERE name = @LogicalFileName vW3Zu B
CREATE TABLE DummyTrans 4'&BpFDUb
(DummyColumn char (8000) not null) ><c5Humr
DECLARE @Counter INT, I=a$1%BzEX
@StartTime DATETIME, }*
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@TruncLog VARCHAR(255) a=VT|CX[
SELECT @StartTime = GETDATE(), 0u2uYiE-l
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' yVzg<%CR^
DBCC SHRINKFILE (@LogicalFileName, @NewSize) :G/]rDtd
EXEC (@TruncLog) |LH*)GrD*t
-- Wrap the log if necessary. uf]$@6)
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired caD;V(
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) va2A@U
AND (@OriginalSize * 8 /1024) > @NewSize IQ~7vk()
BEGIN -- Outer loop. f om"8iL1
SELECT @Counter = 0 e}AJxBE
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) (OQ
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BEGIN -- update ;NeEgqW"
INSERT DummyTrans VALUES ('Fill Log') MiM=fIuw@s
DELETE DummyTrans ][#*h`I
SELECT @Counter = @Counter + 1 1:UC\ WW
END JZxF)]^
EXEC (@TruncLog) *Bsmn!_cB{
END F*:NKT d
SELECT 'Final Size of ' + db_name() + ' LOG is ' + I.1l
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ^VPl>jTg
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' )m;qv'=!
FROM sysfiles n ]}2O4j
WHERE name = @LogicalFileName ?<^AXLiKV
DROP TABLE DummyTrans ?I#hrv@
SET NOCOUNT OFF q|l|mO
8、说明:更改某个表 UyKG$6F?3
exec sp_changeobjectowner 'tablename','dbo' j)6B^!
9、存储更改全部表 [:@?,?V\N
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch $IZZ`Z]B
@OldOwner as NVARCHAR(128), 6 <S&~q
@NewOwner as NVARCHAR(128) bKZ#>%|:o
AS OUO^/]
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DECLARE @Name as NVARCHAR(128) G$uOk?R#5c
DECLARE @Owner as NVARCHAR(128) h]$?~YE
DECLARE @OwnerName as NVARCHAR(128) kA=~8N
DECLARE curObject CURSOR FOR IF}c*uGj}
select 'Name' = name, {bqKb=nyZ
'Owner' = user_name(uid) x]cZm^
from sysobjects 8lSn*;S,
where user_name(uid)=@OldOwner UC/2&7?
order by name v1g5(
OPEN curObject UDtbfc7bk
FETCH NEXT FROM curObject INTO @Name, @Owner 4,ynt&
WHILE(@@FETCH_STATUS=0) Ltd?#HP
BEGIN F>(#Af9
if @Owner=@OldOwner BG0Mj2
begin v/.h%6n?
set @OwnerName = @OldOwner + '.' + rtrim(@Name) &})d%*n
exec sp_changeobjectowner @OwnerName, @NewOwner U*"cf>dB(
end
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-- select @name,@NewOwner,@OldOwner h^ $}1[
FETCH NEXT FROM curObject INTO @Name, @Owner 2BA9T nxC
END 1y-lZ}s_
close curObject aW-o=l@;
deallocate curObject G5y
GO <`UG#6z8
10、SQL SERVER中直接循环写入数据 C_ZD<UPA\
declare @i int H-KwkH`L4
set @i=1 ,Ysl$^\
while @i<30 ,T*_mDVY
begin VD3MJ 8!w
insert into test (userid) values(@i) $_zkq@
set @i=@i+1 m&0BbyE.z
end G_N-}J>EP
小记存储过程中经常用到的本周,本月,本年函数 W)msaq,
Dateadd(wk,datediff(wk,0,getdate()),-1) ~.9o{?pbG
Dateadd(wk,datediff(wk,0,getdate()),6) G,|]a#w&v.
Dateadd(mm,datediff(mm,0,getdate()),0) B~g05`s
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) m?% H<4X
Dateadd(yy,datediff(yy,0,getdate()),0) BRXb<M^;_
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Dke($Jr{
上面的SQL代码只是一个时间段 Yj7= T%5
Dateadd(wk,datediff(wk,0,getdate()),-1) 6aZt4Lw2\
Dateadd(wk,datediff(wk,0,getdate()),6) yki51rOI*
就是表示本周时间段. 3_*Xk.
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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: 'BdmFKy1
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) .>64h H
而在存储过程中 0mD;.1:
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) hi
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) m|2]lb