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。 >K,QP<B
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一、基础 =Hd#"9-
1、说明:创建数据库 0KgP'oWvY
CREATE DATABASE database-name V?G%-+^
2、说明:删除数据库 E' `;
drop database dbname yn]Sc<uK
3、说明:备份sql server Lhux~,EH
--- 创建 备份数据的 device OOXSJE1
USE master 2P8wvNDG
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' w5PscEc
--- 开始 备份 %(khE-SW
BACKUP DATABASE pubs TO testBack fw,,cu`YA
4、说明:创建新表 m{RXt
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) %}zkmEY.e
根据已有的表创建新表: 4D<C;>*/b
A:create table tab_new like tab_old (使用旧表创建新表) O<L=N-
B:create table tab_new as select col1,col2... from tab_old definition only U*Y]cohh
5、说明:删除新表 2/V%jS[4#y
drop table tabname |T/OOIA=sI
6、说明:增加一个列 a5ZXrWv
Alter table tabname add column col type ?uL-qsU
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。 H.;}%id
7、说明:添加主键: Alter table tabname add primary key(col) 3ddw'b'aQ
说明:删除主键: Alter table tabname drop primary key(col) Wj|W B*B
8、说明:创建索引:create [unique] index idxname on tabname(col....) =0EKrG
删除索引:drop index idxname O9By5j 4
注:索引是不可更改的,想更改必须删除重新建。 VPT?z
9、说明:创建视图:create view viewname as select statement wS9V@
删除视图:drop view viewname rYdNn0mhk
10、说明:几个简单的基本的sql语句 "xTVu57Z[
选择:select * from table1 where 范围 XPMUhozV
插入:insert into table1(field1,field2) values(value1,value2) zw+wq+2"
删除:delete from table1 where 范围 Hqs-q4G$
更新:update table1 set field1=value1 where 范围 gAztdAsLM
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! P,)D0i
排序:select * from table1 order by field1,field2 [desc] ey[Z<i1
总数:select count as totalcount from table1 >M{98NH
求和:select sum(field1) as sumvalue from table1 l]wLQqoO
平均:select avg(field1) as avgvalue from table1 `Rt w'Uz
最大:select max(field1) as maxvalue from table1 ><"|>(y
最小:select min(field1) as minvalue from table1 D-C]0Jf3
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11、说明:几个高级查询运算词 Ekq(
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A: UNION 运算符 U7n#TPet
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。 #>:S&R?2t
B: EXCEPT 运算符 :nb|WgEc
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。 EFVZAY"+!;
C: INTERSECT 运算符 ETU-6qFtO
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。 B%Qo6*b
注:使用运算词的几个查询结果行必须是一致的。 EU:N9oT
12、说明:使用外连接 ub>:dNBN
A、left outer join: >/4[OPB0R
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。 #V/{DPz
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 52o^]
B:right outer join: ai?J
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。 2Ul8<${c{
C:full outer join: EHf,VIC8
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 V~/@KU8cH
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二、提升 iOv>g-t:
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) =e# h;x2
法一:select * into b from a where 1<>1 n]4Elrxx
法二:select top 0 * into b from a 'JdK0w#
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) rWNe&gFM
insert into b(a, b, c) select d,e,f from b; L#a!fd
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) )O+Zbn
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 R8lja%+0$
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ?d?.&nt
4、说明:子查询(表名1:a 表名2:b) .J @mpJdY
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) ~ PyS;L}
5、说明:显示文章、提交人和最后回复时间 /2=9i84
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b hVB(*WA^D
6、说明:外连接查询(表名1:a 表名2:b) 7@gH{p1
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Q wG_-
7、说明:在线视图查询(表名1:a ) ZEDvY=@a
select * from (SELECT a,b,c FROM a) T where t.a > 1; tpA-IL?KQw
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 ~Y~M}4
select * from table1 where time between time1 and time2 aizws[C
select a,b,c, from table1 where a not between 数值1 and 数值2 }[!=O+gO
9、说明:in 的使用方法 a)r["*bTx
select * from table1 where a [not] in ('值1','值2','值4','值6') A*+gWn,4Y_
10、说明:两张关联表,删除主表中已经在副表中没有的信息 (c}!gjm
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Dl0{pGK~
11、说明:四表联查问题: W(ryL_#;
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 ..... ,jz~Np_2
12、说明:日程安排提前五分钟提醒 =?y0fLTc
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 l}(HE+?
13、说明:一条sql 语句搞定数据库分页 ; (}~m&p
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 lAo ~w
14、说明:前10条记录 7O|`\&RYR
select top 10 * form table1 where 范围 F%lC%~-qh
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.) ^vSSG5 :
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) X)RgXl{
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 5K?/-0yG
(select a from tableA ) except (select a from tableB) except (select a from tableC) IOxtuR
17、说明:随机取出10条数据 5$:9nPAH
select top 10 * from tablename order by newid() n
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18、说明:随机选择记录 g&w~eWpk
select newid() G~&8/ s
19、说明:删除重复记录 58HAl_8W
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) =IX-n$d`>
20、说明:列出数据库里所有的表名 $i<+O,@-
select name from sysobjects where type='U' Q{=r9&&
21、说明:列出表里的所有的 38X{>*
select name from syscolumns where id=object_id('TableName') =w!9:I&a0
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 "v0bdaQH3
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type ,m0M:!hK
显示结果: mc2uI-W
type vender pcs wS,fj gX
电脑 A 1 7>r[.g
电脑 A 1 |"Zf0G
光盘 B 2 ^K J#dT
光盘 A 2 9:xs)t- _
手机 B 3 z8kebS&5
手机 C 3 V,& OO
23、说明:初始化表table1 e#}Fm;|d
TRUNCATE TABLE table1 -\%5aXr
24、说明:选择从10到15的记录 2auJp
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc `mD!z.`U
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三、技巧 U8>4Cl J4
1、1=1,1=2的使用,在SQL语句组合时用的较多 K9 }Brhe
"where 1=1" 是表示选择全部 "where 1=2"全部不选, vAop#V
如: AH'3
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if @strWhere !='' byt$Wqdl
begin 7 J6Z?
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ct,;V/Dx
end F}[!OYyg
else B9
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begin O.y ?q
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' NB^Al/V@
end DS@Yto
我们可以直接写成 RTg\c[=w
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere bxO/FrwTj{
2、收缩数据库 hCgk78O?
--重建索引 H*N{4zBB
DBCC REINDEX as/PM"
DBCC INDEXDEFRAG Y%TY%"<
--收缩数据和日志 6q`)%"4k
DBCC SHRINKDB WO!OaC?+B,
DBCC SHRINKFILE {/5aF_0D.
3、压缩数据库 o4yl3o
dbcc shrinkdatabase(dbname) x7gd6"10^
4、转移数据库给新用户以已存在用户权限 (w"(RM~
exec sp_change_users_login 'update_one','newname','oldname' WQ:Y NmQ1p
go GZx*A S]+
5、检查备份集 UNv!G/i-5
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' /7+b.h])^
6、修复数据库 PC255
ALTER DATABASE [dvbbs] SET SINGLE_USER :?ZrD,D
GO I!kR:Z
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK RZnmia
GO ]D,_<Kk
ALTER DATABASE [dvbbs] SET MULTI_USER u+6D|
GO KC:6^h'.
7、日志清除 sHPeAa22
SET NOCOUNT ON d>MDC
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DECLARE @LogicalFileName sysname, tV pXA'"!x
@MaxMinutes INT, X+u1p?
@NewSize INT =\)zb '\=d
USE tablename -- 要操作的数据库名 };P=|t(r
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 rxy5Nrue
@MaxMinutes = 10, -- Limit on time allowed to wrap log. >P} XCAU
@NewSize = 1 -- 你想设定的日志文件的大小(M) <RC %<
-- Setup / initialize K(lVAKiP]
DECLARE @OriginalSize int ;;CNr_
SELECT @OriginalSize = size (OwGp3g
FROM sysfiles C}jrx^u>
WHERE name = @LogicalFileName 'T qF}a7
SELECT 'Original Size of ' + db_name() + ' LOG is ' + X6w+L?A
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + suWO:]FR
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' fY78
FROM sysfiles HSU?4=Q
WHERE name = @LogicalFileName SfY9PNck\
CREATE TABLE DummyTrans %FqQ+0^
(DummyColumn char (8000) not null) t"J{qfNs
DECLARE @Counter INT,
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@StartTime DATETIME, #<
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@TruncLog VARCHAR(255) >X:!Y[N
SELECT @StartTime = GETDATE(), K]yWpW
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 3'A0{(b
DBCC SHRINKFILE (@LogicalFileName, @NewSize) fJk'5kv
EXEC (@TruncLog) Sj/v:
-- Wrap the log if necessary. F9las#\J
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired -U9C{q?h
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ku}`PS0UGd
AND (@OriginalSize * 8 /1024) > @NewSize o>yXEg
BEGIN -- Outer loop. MwQt/Qv=
SELECT @Counter = 0 fiU#\%uJg
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) *D[yA
BEGIN -- update %`lJA W[
INSERT DummyTrans VALUES ('Fill Log') b"trg {e
DELETE DummyTrans &{qKoI]
SELECT @Counter = @Counter + 1 >RJ&b
END rADzJ#CU\
EXEC (@TruncLog) KC(z TY
END .EjR<UU
SELECT 'Final Size of ' + db_name() + ' LOG is ' + )^6Os2
CONVERT(VARCHAR(30),size) + ' 8K pages or ' +
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' (w(k*b/
FROM sysfiles AkO);4A;Jd
WHERE name = @LogicalFileName :Zob"*T
DROP TABLE DummyTrans 6<5:m:KE
SET NOCOUNT OFF ln,9v
8、说明:更改某个表 X+,0;% p
exec sp_changeobjectowner 'tablename','dbo' v&]yzl
9、存储更改全部表 ~>0H
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch i tk/1
@OldOwner as NVARCHAR(128), ?0JNaf
@NewOwner as NVARCHAR(128) [^/a`Kda8
AS 2_M+o]Z^
DECLARE @Name as NVARCHAR(128) }o[<1+W(.
DECLARE @Owner as NVARCHAR(128) q j9q
DECLARE @OwnerName as NVARCHAR(128) 61gyx6v
DECLARE curObject CURSOR FOR DYgB_Iak
select 'Name' = name, uT<<G)v)
'Owner' = user_name(uid) 9^Web~yi#
from sysobjects MI:%Eq
where user_name(uid)=@OldOwner d`5AQfL&
order by name ~MYE8xrId
OPEN curObject 9~a 5R]x2
FETCH NEXT FROM curObject INTO @Name, @Owner P-8QXDdr
WHILE(@@FETCH_STATUS=0) LH`2Y,E
BEGIN nf&5oE^
if @Owner=@OldOwner $o$WFV+h
begin /<k5"C%z
set @OwnerName = @OldOwner + '.' + rtrim(@Name) UH\{:@GjNO
exec sp_changeobjectowner @OwnerName, @NewOwner :kwDa
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end E
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-- select @name,@NewOwner,@OldOwner 1:@ScHS
FETCH NEXT FROM curObject INTO @Name, @Owner ke<5]&x
END Lh.-*H
close curObject >@4AxV\
deallocate curObject 3kF+wifsz
GO R1%J6wZq
10、SQL SERVER中直接循环写入数据 CW/L(RQ
declare @i int A9"!=/~
set @i=1 ^\J-LU|"B
while @i<30 GY0OVAW6'c
begin R2 J A(Hn
insert into test (userid) values(@i) =
8y,7u)
set @i=@i+1 jWh)bsqI!
end !)W#|sys&
小记存储过程中经常用到的本周,本月,本年函数 ]Ge>S?u
Dateadd(wk,datediff(wk,0,getdate()),-1) ryA+Lli.
Dateadd(wk,datediff(wk,0,getdate()),6) |68/FJZ,5
Dateadd(mm,datediff(mm,0,getdate()),0) -O-?hsV)y
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) g4 +Hq *
Dateadd(yy,datediff(yy,0,getdate()),0) ZB/1I;l`c
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) q6>}
上面的SQL代码只是一个时间段 }? c%L8\
Dateadd(wk,datediff(wk,0,getdate()),-1) =]pEvj9o
Dateadd(wk,datediff(wk,0,getdate()),6) Z ZCm438
就是表示本周时间段. R1<$VR
下面的SQL的条件部分,就是查询时间段在本周范围内的: ^~@3X[No
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ;<GxonIV
而在存储过程中 JV'aqnb.8\
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) +qT+iHa|n
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 8$ #z>