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。 Q7*SE%H
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一、基础 >CrA;\l
1、说明:创建数据库 <<@bl@9'
CREATE DATABASE database-name 5Eg1Q
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2、说明:删除数据库 1|RANy
drop database dbname ,#Iu
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3、说明:备份sql server EwuO&q
--- 创建 备份数据的 device %{ABaeb]
USE master d^RxQuA
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' IHe/xQ@
--- 开始 备份 /~}}"zx&
BACKUP DATABASE pubs TO testBack `Zf^E
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4、说明:创建新表 1HXjN~XF
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) DAS/43\
根据已有的表创建新表: p=;=w_^y
A:create table tab_new like tab_old (使用旧表创建新表) aIJt0;
B:create table tab_new as select col1,col2... from tab_old definition only ~5_Ad\n9
5、说明:删除新表 pv*,gSS
drop table tabname 18~>ZR
6、说明:增加一个列 (}a8"]Z
Alter table tabname add column col type 9bP^`\K[N
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@;J]x(
7、说明:添加主键: Alter table tabname add primary key(col) gGr^@=;YC
说明:删除主键: Alter table tabname drop primary key(col) HIQ_%L4]
8、说明:创建索引:create [unique] index idxname on tabname(col....) 0KYEb%44
删除索引:drop index idxname
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注:索引是不可更改的,想更改必须删除重新建。 nTuJEFn{
9、说明:创建视图:create view viewname as select statement IAYR+c
删除视图:drop view viewname 2HpHxVJ
10、说明:几个简单的基本的sql语句 D&/kCi= R
选择:select * from table1 where 范围 k,'L}SK
插入:insert into table1(field1,field2) values(value1,value2) ' qWALu
删除:delete from table1 where 范围 m5L-67[sB
更新:update table1 set field1=value1 where 范围 K&nE_.kbl
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 4xk|F'6K
排序:select * from table1 order by field1,field2 [desc] %`OJ.:k
总数:select count as totalcount from table1 }E0,z
求和:select sum(field1) as sumvalue from table1 .Si,dc\
平均:select avg(field1) as avgvalue from table1 *FC=X) _&W
最大:select max(field1) as maxvalue from table1 P\w\N2
最小:select min(field1) as minvalue from table1 eCN })An
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11、说明:几个高级查询运算词 #.it]Nv{
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A: UNION 运算符 ,RJtm%w
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。 /a^1_q-bX
B: EXCEPT 运算符 fBalTk;G{U
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。 z8QAo\_I(
C: INTERSECT 运算符 :|_'fNd+!
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。 &=#[(vl
注:使用运算词的几个查询结果行必须是一致的。 *+-}P|S:
12、说明:使用外连接 X *&[u7No
A、left outer join: E_k$W5
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。 ~KW,kyXBnD
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 Qj,]N@7
B:right outer join: 7[I}*3Q'
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。 7N-w eX
C:full outer join: :,Pn3xl
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。 y=`2\L" O
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二、提升 .z
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Q7R~{5r>W
法一:select * into b from a where 1<>1 ZT,B(#m
法二:select top 0 * into b from a T?
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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) j:k[90
insert into b(a, b, c) select d,e,f from b; '`eO\huf
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) KMU4n-s"o
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 \=uKHNP?#
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. "ul {d(K3
4、说明:子查询(表名1:a 表名2:b) ]3VI|f$$
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) <1FC%f/
5、说明:显示文章、提交人和最后回复时间 G]fRk^~
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 29!q!g |
6、说明:外连接查询(表名1:a 表名2:b) ?%`@ub$
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c X=hYB}}nu
7、说明:在线视图查询(表名1:a ) BDq%'~/^
select * from (SELECT a,b,c FROM a) T where t.a > 1; 9:,V5n=
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 &Rx{.9
select * from table1 where time between time1 and time2 ,_yhz0.
select a,b,c, from table1 where a not between 数值1 and 数值2 /x5rf
9、说明:in 的使用方法 VCn{mp*h
select * from table1 where a [not] in ('值1','值2','值4','值6') an|x$e7|?
10、说明:两张关联表,删除主表中已经在副表中没有的信息 p8Q,@ql.
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) HR
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11、说明:四表联查问题: )^4\,u\@
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... T(e!_VY|m
12、说明:日程安排提前五分钟提醒 3T"j)R_=l
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 2C/$Ei^t
13、说明:一条sql 语句搞定数据库分页 /h*>P:i].
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 P^w#S
14、说明:前10条记录 v1%uxthW
select top 10 * form table1 where 范围 kB'Fkqwm
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.) Eve.QAl|
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) mMb'@
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 UG)8D5
(select a from tableA ) except (select a from tableB) except (select a from tableC) QS{1CC9$
17、说明:随机取出10条数据 TYJ:!
select top 10 * from tablename order by newid() 3~}uqaGt
18、说明:随机选择记录 T{Sb^-H#X
select newid() Z$0uH* h
19、说明:删除重复记录 gA:5M
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) TQx.KM>y
20、说明:列出数据库里所有的表名 IG|X!l
select name from sysobjects where type='U' Au4yBm
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21、说明:列出表里的所有的 r41\r,`Dj
select name from syscolumns where id=object_id('TableName') pcT:]d[1)
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 :cq9f2)
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 0TGLM#{
显示结果: >S'17D
type vender pcs } p&&_?
电脑 A 1 VJdIHsI
电脑 A 1 \RvvHty-V
光盘 B 2 o(:[r@Z0z
光盘 A 2
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手机 B 3 CAcS~ "
手机 C 3 "\}@gV#r$A
23、说明:初始化表table1 xER\ZpA:,
TRUNCATE TABLE table1 rb1`UG"h$
24、说明:选择从10到15的记录 >TQH|}|6(y
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc +m8!U=Zi
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三、技巧 QNARkYY~|
1、1=1,1=2的使用,在SQL语句组合时用的较多 iMs5zf<M
"where 1=1" 是表示选择全部 "where 1=2"全部不选, hRty [
如: WHjUR0NZ
if @strWhere !='' WDg+J
begin $OP7l>KZY
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere >2,Gy-&"0
end }; f#^gz'
else !<SA6m#
begin >y[oP!-|P
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 9'{}!-(xR
end l2l(_$@3
我们可以直接写成 6xZ=^;H
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere tQH+)*
2、收缩数据库 %*&UJpbA
--重建索引 2Z3('?\z~
DBCC REINDEX U2`'qsR1
DBCC INDEXDEFRAG Q5FM8Q
--收缩数据和日志 ^my].Qpt
DBCC SHRINKDB *cC_j*1@
DBCC SHRINKFILE rFC" Jx
3、压缩数据库 =:/BV=tv
dbcc shrinkdatabase(dbname) !"<MsoY@
4、转移数据库给新用户以已存在用户权限 e46/{4F,
exec sp_change_users_login 'update_one','newname','oldname' /\H>y
go LE*h9((
5、检查备份集 aj?a^}X
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' I_xXDr
6、修复数据库 2n `S5(V
ALTER DATABASE [dvbbs] SET SINGLE_USER =k/IaFg 6w
GO mZx&Xez_G
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK cZT({uYGL
GO M-;4
ALTER DATABASE [dvbbs] SET MULTI_USER lWqrU1Sjl
GO # g_Bx
7、日志清除 #/I[Jqf
SET NOCOUNT ON ]|sAK%/
DECLARE @LogicalFileName sysname, nv0]05.4
@MaxMinutes INT, NMww>80
@NewSize INT vP!{",>
USE tablename -- 要操作的数据库名 K^B%/T]d
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 $dA-2e10
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Q" ,0F{'
@NewSize = 1 -- 你想设定的日志文件的大小(M) 8HR mQ
-- Setup / initialize e0J6Ae4V[
DECLARE @OriginalSize int z,VD=Hnz
SELECT @OriginalSize = size LrATSq@
FROM sysfiles Ma+$g1$
WHERE name = @LogicalFileName bks/`rIA
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ed:@C?
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Z7RiPSdxp
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' m+#iR}*1L
FROM sysfiles ET[kpL
WHERE name = @LogicalFileName TOoQZTI
CREATE TABLE DummyTrans SF5@Vg
(DummyColumn char (8000) not null) i:Zm*+Gi
DECLARE @Counter INT, hs?sGr
@StartTime DATETIME, +e-G,%>9
@TruncLog VARCHAR(255) JqMDqPIQ
SELECT @StartTime = GETDATE(), ZKXo-~=>
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' !>>f(t4
DBCC SHRINKFILE (@LogicalFileName, @NewSize) .VkbYK
EXEC (@TruncLog) cKn`/\.H
-- Wrap the log if necessary. 'w14sr%
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 1*dRK6
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Bf$_XG3
AND (@OriginalSize * 8 /1024) > @NewSize !YP@m~
BEGIN -- Outer loop. (XXheC
SELECT @Counter = 0 P9S2?Q
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) }sx_Yj
BEGIN -- update hAm`NJMSO
INSERT DummyTrans VALUES ('Fill Log') I8QjKI (
DELETE DummyTrans l983vKr
SELECT @Counter = @Counter + 1 %/>Y/!;
END 9JWa$iBH@
EXEC (@TruncLog) Rcawc
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END JXw^/Y$
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ~j-cS
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + #Jna6
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' HmZ{L +"
FROM sysfiles uio@r^Xz
WHERE name = @LogicalFileName KL ?@@7
DROP TABLE DummyTrans :Dd$i_3=
SET NOCOUNT OFF +n7?S~R$
8、说明:更改某个表 \'M3|w`f
exec sp_changeobjectowner 'tablename','dbo' ~u.T- 0F
9、存储更改全部表 .S%0
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch JkGnKm9G
@OldOwner as NVARCHAR(128), \tRG1&{$%
@NewOwner as NVARCHAR(128) e#B#B
AS rvyrxw%[
DECLARE @Name as NVARCHAR(128) NNF>Xa`9,
DECLARE @Owner as NVARCHAR(128) e{KByFl
DECLARE @OwnerName as NVARCHAR(128) UK{irU|\
DECLARE curObject CURSOR FOR F
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select 'Name' = name, |Xw/E)jA
'Owner' = user_name(uid) '}rRzD:
from sysobjects l9Q(xuhv
where user_name(uid)=@OldOwner ay
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order by name 1-PoZ[p-R
OPEN curObject $-c!W!H
FETCH NEXT FROM curObject INTO @Name, @Owner n=,\;3Y=
WHILE(@@FETCH_STATUS=0) !sRngXCXk?
BEGIN ~l$3uN[g
if @Owner=@OldOwner IJJ%$%F/
begin F|&{Rt
set @OwnerName = @OldOwner + '.' + rtrim(@Name) k2xHH$+{#=
exec sp_changeobjectowner @OwnerName, @NewOwner m] W5+
end cS. -7
-- select @name,@NewOwner,@OldOwner (4@lKKiU%H
FETCH NEXT FROM curObject INTO @Name, @Owner 5o/&T"]@
END 1pCieTz!PN
close curObject 6O@J7P
deallocate curObject kEO7PK/
GO 0[F:'_
10、SQL SERVER中直接循环写入数据 fS:1^A2,
declare @i int @m?QR(LJ
set @i=1 !I\!;b
while @i<30 &h~Xq^
begin 4HAp{a1
insert into test (userid) values(@i) ||zb6|7I4
set @i=@i+1 :iiw3#]
end >I<r)w]
小记存储过程中经常用到的本周,本月,本年函数 )?2e
Dateadd(wk,datediff(wk,0,getdate()),-1) #eN{!Niy&U
Dateadd(wk,datediff(wk,0,getdate()),6) )9S>ZZF
Dateadd(mm,datediff(mm,0,getdate()),0) }@+NN
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) q\rC5gk>
Dateadd(yy,datediff(yy,0,getdate()),0) CdUAy|!`R
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) N-g8}03
上面的SQL代码只是一个时间段 ?DH"V7bs
Dateadd(wk,datediff(wk,0,getdate()),-1) '&99?s`u
Dateadd(wk,datediff(wk,0,getdate()),6) xcJ`1*1N
就是表示本周时间段. QW_agm
下面的SQL的条件部分,就是查询时间段在本周范围内的: A!vCb
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) +p8BGNW,
而在存储过程中 P"lBB8\eku
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ;Efcw[<
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) dDDGM:]