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。 mz$Wo *FB
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一、基础 iC|6roO!jk
1、说明:创建数据库 QjjJtKz
CREATE DATABASE database-name y~c4:*L3
2、说明:删除数据库 >)J47j7{c
drop database dbname h}`&]2|]
3、说明:备份sql server PP[)h,ZL*
--- 创建 备份数据的 device q8xc70: R
USE master
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' yp2 'KES>
--- 开始 备份 /zG-\e U
BACKUP DATABASE pubs TO testBack @7l=+`.i
4、说明:创建新表 W3{<e"
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 1Q&WoJLfR
根据已有的表创建新表: .)^3t~
A:create table tab_new like tab_old (使用旧表创建新表) w[YkTv
B:create table tab_new as select col1,col2... from tab_old definition only 3w^J"O/T
5、说明:删除新表 9HNh*Gc=
drop table tabname :^-HVT)qF
6、说明:增加一个列 w] 5U
Alter table tabname add column col type =Mu'+,dT
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 ^I'Lw
7、说明:添加主键: Alter table tabname add primary key(col) 1f@U:<:
说明:删除主键: Alter table tabname drop primary key(col) xH`j7qK.
8、说明:创建索引:create [unique] index idxname on tabname(col....) ]IHD:!Z-=
删除索引:drop index idxname *@G(3 n
注:索引是不可更改的,想更改必须删除重新建。 0'%+X|
9、说明:创建视图:create view viewname as select statement cfC; eRgq~
删除视图:drop view viewname g3|Y$/J7P
10、说明:几个简单的基本的sql语句 ^E<~zO=Z
选择:select * from table1 where 范围 )0n29
插入:insert into table1(field1,field2) values(value1,value2) #}t1
删除:delete from table1 where 范围 (J^Lqh_
更新:update table1 set field1=value1 where 范围 q]iKz%|Z/
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! %KJhtd"q
排序:select * from table1 order by field1,field2 [desc] im4e!gRE
总数:select count as totalcount from table1 .sJys SA\
求和:select sum(field1) as sumvalue from table1 0.u9f`04
平均:select avg(field1) as avgvalue from table1 TM/|K|_
最大:select max(field1) as maxvalue from table1 B'KXQa-$O
最小:select min(field1) as minvalue from table1 9o_ g_q
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11、说明:几个高级查询运算词 e"o6C\c
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A: UNION 运算符 J:~[j
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 p-Rm,xyL%
B: EXCEPT 运算符 -VreBKn
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 "
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C: INTERSECT 运算符 O{")i;v@
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 y?Hj%,
注:使用运算词的几个查询结果行必须是一致的。 EG(`E9DZ
12、说明:使用外连接 wcdW72
A、left outer join: J:g<RZZ1
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 Z/NGv
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 1C}pv{0:&
B:right outer join: A"\P&kqMV
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 KD%xo/Z.
C:full outer join: EU^}NZW&v:
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 cwM#X;FGq
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二、提升 nCffBc
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) e8XM=$@
法一:select * into b from a where 1<>1 VW{aUgajO
法二:select top 0 * into b from a kO..~@aY
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) kwDh|K
insert into b(a, b, c) select d,e,f from b; ^Hz
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) !7mvyc!'!
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 (E"&UC[
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Rm,[D)D^0N
4、说明:子查询(表名1:a 表名2:b) _XY`UZ
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) <K DH
5、说明:显示文章、提交人和最后回复时间 S.Wh4kMUe
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b HQ|o%9~
6、说明:外连接查询(表名1:a 表名2:b) 1qm/{>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 l5ZADK4
7、说明:在线视图查询(表名1:a ) 097Fvt=#
select * from (SELECT a,b,c FROM a) T where t.a > 1; #L@} .Giz
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 pW*{Mx
select * from table1 where time between time1 and time2 ~8H&m,{j
select a,b,c, from table1 where a not between 数值1 and 数值2 m0xJ05Zx
9、说明:in 的使用方法 5YTb7M
select * from table1 where a [not] in ('值1','值2','值4','值6') zmy4tsmX
10、说明:两张关联表,删除主表中已经在副表中没有的信息 0v_6cYA
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 8X}^~ e
11、说明:四表联查问题: 45Nv_4s
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 ..... g:3d<CS
12、说明:日程安排提前五分钟提醒 msA' 5>
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ShL1'Z}^{
13、说明:一条sql 语句搞定数据库分页 X[GIOPDx
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 `DgaO-Dg3
14、说明:前10条记录 #Acon7Rp
select top 10 * form table1 where 范围 (TT3(|v
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.) :DOr!PNA
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) o9KyAP$2
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 bc3|;O
(select a from tableA ) except (select a from tableB) except (select a from tableC) [+hy_Nc$
17、说明:随机取出10条数据 Y=P9:unG
select top 10 * from tablename order by newid() Gt^|+[gD
18、说明:随机选择记录 T7>48eH
select newid() I!|y;mh:it
19、说明:删除重复记录 :Az8K )
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ttK,((=@
20、说明:列出数据库里所有的表名 #d}0}7ue
select name from sysobjects where type='U' 4o1Q7
21、说明:列出表里的所有的 :0
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select name from syscolumns where id=object_id('TableName') tx^92R2/
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。 4)3g!o?
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 d u.HSXK
显示结果: Zw;$(="
type vender pcs O{lIs_1.Z
电脑 A 1 8yHq7=
电脑 A 1 qiG]nCq
光盘 B 2 a(PjcQ4dY
光盘 A 2 -vyIOH,
手机 B 3 #5'c\\?Q
手机 C 3 jo 7Hyw!g
23、说明:初始化表table1 JfI aOhKs]
TRUNCATE TABLE table1 +IwdMJ8&8
24、说明:选择从10到15的记录 %iK%$
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Pk$}%;@v
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三、技巧 2-B6IPeI
1、1=1,1=2的使用,在SQL语句组合时用的较多 9uA,
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, Y*5Z)h
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如: 7ZS>1
if @strWhere !='' UJ7'JBT=k
begin jK3giT
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere T$: >*
end ?cqicN.+6
else gJ]Cq/gC
begin DBQOxryP>o
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ?"()>PJx
end oUl=l}qnD
我们可以直接写成 Kg4QT/0VA
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere zt7_r`#z
2、收缩数据库 hNH.G(l0
--重建索引 *,E;
DBCC REINDEX kxwNbxC
DBCC INDEXDEFRAG eeZIa`.sX
--收缩数据和日志 3CA|5A.Pa
DBCC SHRINKDB RxlszyE
DBCC SHRINKFILE Zw2jezP@t
3、压缩数据库 fp9rO}##
dbcc shrinkdatabase(dbname) W\HLal
4、转移数据库给新用户以已存在用户权限 ;l$9gD>R
exec sp_change_users_login 'update_one','newname','oldname' n"(7dl?
go BmJkt3j."
5、检查备份集 ZrFr`L5F;
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Bx+d3
6、修复数据库 *y)4D[
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ALTER DATABASE [dvbbs] SET SINGLE_USER #0}Ok98P
GO )J;ny!^2
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 9Tqo LX
GO uQ{=o]sy
ALTER DATABASE [dvbbs] SET MULTI_USER 0('OyH)
GO aL88E
7、日志清除 \s,Iz[0Vfz
SET NOCOUNT ON 7@FDBjq
DECLARE @LogicalFileName sysname, Kp8fh-4_
@MaxMinutes INT, )V=0IZi
@NewSize INT V{43HA10b
USE tablename -- 要操作的数据库名 xC<R:"Mn
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 |a%B|CX
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 5i|s>pD4z1
@NewSize = 1 -- 你想设定的日志文件的大小(M) ):/,w!1
-- Setup / initialize
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DECLARE @OriginalSize int PoJmW^:}
SELECT @OriginalSize = size `tX@8|
FROM sysfiles lco~X DI
WHERE name = @LogicalFileName Ud$Q0m&
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ])eOa%
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + U9x4j_.q
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' pfR"s:#
FROM sysfiles +e U`H[iu
WHERE name = @LogicalFileName ?2/uSG|
CREATE TABLE DummyTrans *nLIXnm
(DummyColumn char (8000) not null) <} &7 a s
DECLARE @Counter INT, BlL|s=dlQV
@StartTime DATETIME, w2k<)3 g~
@TruncLog VARCHAR(255) -<xyC8$^$
SELECT @StartTime = GETDATE(), :MK=h;5Z
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' B#1:Y;Z
DBCC SHRINKFILE (@LogicalFileName, @NewSize) " <qEXX
EXEC (@TruncLog) b9`i Z
-- Wrap the log if necessary. Jth=.9mrM
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired C9o$9 l+B
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) WPtMds4
AND (@OriginalSize * 8 /1024) > @NewSize J`W-]3S#
BEGIN -- Outer loop. A1Ka(3"
SELECT @Counter = 0 "t=UX
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) &D]&UQf
BEGIN -- update 5qC:yI
INSERT DummyTrans VALUES ('Fill Log') }X.>4\B5
DELETE DummyTrans 3!>/smb!
SELECT @Counter = @Counter + 1 +yCTH
END .xEJaID\N
EXEC (@TruncLog) )9MrdVNv
END
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + QGXQ {
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + B "*`R!y
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 3&$Nd
FROM sysfiles #VO.%H}i
WHERE name = @LogicalFileName Ey'J]KVW
DROP TABLE DummyTrans Vd21,~^>g
SET NOCOUNT OFF sllzno2bU
8、说明:更改某个表 W+.{4K
exec sp_changeobjectowner 'tablename','dbo' IJ0#iA. T
9、存储更改全部表 7RD$=?o O'
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch #K|0laul
@OldOwner as NVARCHAR(128), \04mLIJr9
@NewOwner as NVARCHAR(128) `os8;`G
AS 6%E~p0)i%
DECLARE @Name as NVARCHAR(128) Rnr#$C%
DECLARE @Owner as NVARCHAR(128) +ZclGchw
DECLARE @OwnerName as NVARCHAR(128) "?P[9x}
DECLARE curObject CURSOR FOR L@nebT;\'
select 'Name' = name, BMpF02Y|4
'Owner' = user_name(uid) .A(i=!{q
from sysobjects |:N>8%@6c
where user_name(uid)=@OldOwner ocwE_dR{
order by name +1/b^Ac
OPEN curObject +qhnP$vIe
FETCH NEXT FROM curObject INTO @Name, @Owner mpAHL(
WHILE(@@FETCH_STATUS=0) q4k.f_{
BEGIN {c@G$
if @Owner=@OldOwner @UO}W_0ZD
begin }"n7~|
set @OwnerName = @OldOwner + '.' + rtrim(@Name) qi&D+~Gv!
exec sp_changeobjectowner @OwnerName, @NewOwner Ib6(Bp9.L
end d/]|657u
-- select @name,@NewOwner,@OldOwner k1#5nYN.
FETCH NEXT FROM curObject INTO @Name, @Owner ljVIE/iq
END a8zZgIV
close curObject nkRK+~>
deallocate curObject E?cZbn*>`
GO lVoik*,B
10、SQL SERVER中直接循环写入数据 ETO$9}x[
declare @i int @(>XOj?+
set @i=1 [zQWyDu
while @i<30 T9?54r
begin 3 z=\.R
insert into test (userid) values(@i) v,jhE9_O0
set @i=@i+1 =U"dPLax
end f`?0WJ(M
小记存储过程中经常用到的本周,本月,本年函数 Oc~aW3*A(
Dateadd(wk,datediff(wk,0,getdate()),-1) B6MkF"J<
Dateadd(wk,datediff(wk,0,getdate()),6) M&f#wQ
Dateadd(mm,datediff(mm,0,getdate()),0) RLHYw@-j@
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ybE[B}pOeZ
Dateadd(yy,datediff(yy,0,getdate()),0) 3cixQzb}u
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) yj
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上面的SQL代码只是一个时间段 ~RInN+N#
Dateadd(wk,datediff(wk,0,getdate()),-1) @VK6JjIq
Dateadd(wk,datediff(wk,0,getdate()),6) VoM6
就是表示本周时间段. "r. .
下面的SQL的条件部分,就是查询时间段在本周范围内的: OJpj}R
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 'E -FO_N
而在存储过程中 ^C7C$TZS
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) G6Nb{m
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) a+Ab]m8`