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。 ,f""|X5
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一、基础 HC`3AQ12!&
1、说明:创建数据库 8QgL7
CREATE DATABASE database-name .2- JV0
2、说明:删除数据库 &!EYT0=>p
drop database dbname ~0$F
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3、说明:备份sql server pD.@&J~
--- 创建 备份数据的 device mZJzBYM)
USE master 3e<^-e)+xL
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' QZq9$;>dW
--- 开始 备份 bB:X<
BACKUP DATABASE pubs TO testBack = 8e8!8
4、说明:创建新表 T1]X
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) vrldRn'*9
根据已有的表创建新表: uTloj.
A:create table tab_new like tab_old (使用旧表创建新表) >Ezwl5b
B:create table tab_new as select col1,col2... from tab_old definition only Xr6 !b:UX
5、说明:删除新表 U[ungvU1U
drop table tabname .7^-*HT}
6、说明:增加一个列 1X}Tp\e
Alter table tabname add column col type a9_KQ=&CI
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。 JBJ7k19;
7、说明:添加主键: Alter table tabname add primary key(col) 40sLZa)e
说明:删除主键: Alter table tabname drop primary key(col) 7%FZXsD
8、说明:创建索引:create [unique] index idxname on tabname(col....) #\;w::
删除索引:drop index idxname HPH {{p
注:索引是不可更改的,想更改必须删除重新建。 ; SM^
9、说明:创建视图:create view viewname as select statement 13az[
删除视图:drop view viewname NKh{iSLm
10、说明:几个简单的基本的sql语句 ~"YNG?Rre
选择:select * from table1 where 范围 bHT@]`@@
插入:insert into table1(field1,field2) values(value1,value2) c\ *OId1{;
删除:delete from table1 where 范围 swgBPJ"?
更新:update table1 set field1=value1 where 范围 {!?RG\EYN
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! pNWp3+a'
排序:select * from table1 order by field1,field2 [desc] IbaL.t\>
总数:select count as totalcount from table1 Z|GkM5QH:
求和:select sum(field1) as sumvalue from table1 Bj[/tQ
平均:select avg(field1) as avgvalue from table1 EKw\a
最大:select max(field1) as maxvalue from table1 ll09j Ef
最小:select min(field1) as minvalue from table1 h4i$z-!
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11、说明:几个高级查询运算词 Z69IHA[
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A: UNION 运算符 fb;"J+
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 |;-r};
B: EXCEPT 运算符 "kg$s5o
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。 D*Q#G/TF3
C: INTERSECT 运算符 @h,$&=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。 ~8{3Fc 0
注:使用运算词的几个查询结果行必须是一致的。 sYI':UQe
12、说明:使用外连接 'vIkA=
A、left outer join: 5hK\YTU
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。 LkB!:+v |B
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 .4(f0RG
B:right outer join: *03/:q ^(
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。 v('d H"Y
C:full outer join: *?"{T;4u~O
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。 <BA&S
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二、提升 jdf@lb=5l
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) y]%,Y=%X
法一:select * into b from a where 1<>1 cN>i3}fq
法二:select top 0 * into b from a F
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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) m3-J0D<
insert into b(a, b, c) select d,e,f from b; _=x_"rzx
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) xB+H7Ya
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 eF1%5;" W
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. XOU$3+8q5
4、说明:子查询(表名1:a 表名2:b) Q0_W<+`
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) c/U6K
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5、说明:显示文章、提交人和最后回复时间 @v=q,A8_
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b =1[g`b
6、说明:外连接查询(表名1:a 表名2:b) VrxH6 Y
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c BAHx7x#(
7、说明:在线视图查询(表名1:a ) ~mU_`o
select * from (SELECT a,b,c FROM a) T where t.a > 1; kR(=VM JU
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 2f4c;YS
select * from table1 where time between time1 and time2 lHqx}n@e
select a,b,c, from table1 where a not between 数值1 and 数值2 jy2nn:1#^
9、说明:in 的使用方法 1iDo$]TEK
select * from table1 where a [not] in ('值1','值2','值4','值6') Af<>O$$6
10、说明:两张关联表,删除主表中已经在副表中没有的信息 W10fjMC}^
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) d]`,}vi#E9
11、说明:四表联查问题: J,Ap9HJt
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 ..... ;P~S/j[ 8
12、说明:日程安排提前五分钟提醒 - S-1<xR
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 S>E.*]_
13、说明:一条sql 语句搞定数据库分页 J@iN':l-
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 3Q)>gh*
14、说明:前10条记录 nWu4HFi
select top 10 * form table1 where 范围 ]l%.X7M9
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.) j@!}r|-T
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) -rlX<(pl)
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 -`EoTXT*U
(select a from tableA ) except (select a from tableB) except (select a from tableC) cvfAa#tq>
17、说明:随机取出10条数据 j56 An6g
select top 10 * from tablename order by newid() p]eD@3Wz
18、说明:随机选择记录 c<e\JJY5?
select newid() $twF93u$
19、说明:删除重复记录 I!D*( >
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) v{Vesf
20、说明:列出数据库里所有的表名 3fTI&2:
select name from sysobjects where type='U' $(=1A>40
21、说明:列出表里的所有的 0 XzO`*
select name from syscolumns where id=object_id('TableName') -~f.>@Wb
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 #+k[[; 0
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type yFsXI0I[p
显示结果: pnJT]?},
type vender pcs QGy=JHb
电脑 A 1 tvRy8u;
电脑 A 1 UV.9KcN.
光盘 B 2 (=rv `1
光盘 A 2 UUqj?'Nv
手机 B 3 pa-4|)qY
手机 C 3 jF9CTL<
23、说明:初始化表table1 m)}MkC-
TRUNCATE TABLE table1 id'#s
24、说明:选择从10到15的记录 Kf~+jYobO
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc G1tp
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三、技巧 GR
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1、1=1,1=2的使用,在SQL语句组合时用的较多 2z3A"HrlA
"where 1=1" 是表示选择全部 "where 1=2"全部不选, F2'cL @E3
如: [hbp#I~*[
if @strWhere !='' 'qE
begin B$EP'5@b
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere g<%-n,
end a*ymBGF
else :`1g{8.+
begin k1zt|
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' i{qU RP}.
end ts>}>}@vc
我们可以直接写成 "s9gQAoaO
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere sb.SpF>
2、收缩数据库 Dj"=kL0
--重建索引 [)n}!5fE
DBCC REINDEX }4%)m
DBCC INDEXDEFRAG _Qc\v0%
--收缩数据和日志 Qpf]3
DBCC SHRINKDB I3Xh[% -!
DBCC SHRINKFILE HYmXPpse
3、压缩数据库 S]O Hv6
dbcc shrinkdatabase(dbname) k|'Mh0G0
4、转移数据库给新用户以已存在用户权限 caD;V(
exec sp_change_users_login 'update_one','newname','oldname' va2A@U
go P@`"MNS
5、检查备份集 f om"8iL1
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' e}AJxBE
6、修复数据库 X(28xbd|
ALTER DATABASE [dvbbs] SET SINGLE_USER ;NeEgqW"
GO 1G.gPx[
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ?ovGYzUZ
GO {`CWzk?
ALTER DATABASE [dvbbs] SET MULTI_USER ZY$@_D OB}
GO *Bsmn!_cB{
7、日志清除 BK SK@OV
SET NOCOUNT ON f`=T@nA
DECLARE @LogicalFileName sysname, ^VPl>jTg
@MaxMinutes INT, dvF48,kr
@NewSize INT n ]}2O4j
USE tablename -- 要操作的数据库名 FH`&C*/F0Y
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 m-92G8'
@MaxMinutes = 10, -- Limit on time allowed to wrap log. <OSvRWP)
@NewSize = 1 -- 你想设定的日志文件的大小(M) 1[9j`~[([
-- Setup / initialize CT%m_lN
DECLARE @OriginalSize int eH/\7)z
SELECT @OriginalSize = size AiHf?"EVT
FROM sysfiles z
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WHERE name = @LogicalFileName T<k1?h^7
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^oO5t-9<!
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ^ZWFj?`\UV
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' V_622~Tc/[
FROM sysfiles W+C_=7_
WHERE name = @LogicalFileName 8;&S9'ci
CREATE TABLE DummyTrans g@VndAp
(DummyColumn char (8000) not null) _rd j,F8
DECLARE @Counter INT, 0(9@GIT
@StartTime DATETIME, Am0C|(#Xm
@TruncLog VARCHAR(255) q*TKs#3
SELECT @StartTime = GETDATE(), g_c)Ts(
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' bv>lm56
DBCC SHRINKFILE (@LogicalFileName, @NewSize) bTp2)a^G
EXEC (@TruncLog) a;(zH*/XK
-- Wrap the log if necessary. JM lhBh
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired utJVuJw:t
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) #(g+jb0E
AND (@OriginalSize * 8 /1024) > @NewSize b7sE
BEGIN -- Outer loop. m>dcb
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SELECT @Counter = 0 y]f^`2L!8>
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) lA-!~SM v"
BEGIN -- update ey\{C`(__y
INSERT DummyTrans VALUES ('Fill Log') 'oQP:*Btl3
DELETE DummyTrans s
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SELECT @Counter = @Counter + 1 z T T
END AeCG2!8^0
EXEC (@TruncLog) MYSc*G
END )\\V
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + h21(K}
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + }Rxg E~F
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' "`*a)'.'^c
FROM sysfiles gLMea:
WHERE name = @LogicalFileName Rue|<d1
DROP TABLE DummyTrans ;s.5\YZ"k
SET NOCOUNT OFF Q1\k`J
8、说明:更改某个表 $"{3yLg
exec sp_changeobjectowner 'tablename','dbo' zQ %z"tQ
9、存储更改全部表 'qF3,Rw
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch X+E\]X2
@OldOwner as NVARCHAR(128), 'L|GClc6)
@NewOwner as NVARCHAR(128) 'S4EKV]
AS
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DECLARE @Name as NVARCHAR(128) RzJ}C T
DECLARE @Owner as NVARCHAR(128) p6y0W`U
DECLARE @OwnerName as NVARCHAR(128) qTh='~m4[
DECLARE curObject CURSOR FOR ka)LK@p6
select 'Name' = name, ^ lc}FN
'Owner' = user_name(uid) :`u&TXsu
from sysobjects M:UB>-`bW
where user_name(uid)=@OldOwner Ld3Bi2d|
order by name $<
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OPEN curObject hN:F8r+DG
FETCH NEXT FROM curObject INTO @Name, @Owner 5ZyBP~
WHILE(@@FETCH_STATUS=0) ) UDJ[pL@
BEGIN avt>saR
if @Owner=@OldOwner x+y!P
begin j YIV^o 0
set @OwnerName = @OldOwner + '.' + rtrim(@Name) }8F$&
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exec sp_changeobjectowner @OwnerName, @NewOwner "i{_<;p O
end x1V2|~;p|
-- select @name,@NewOwner,@OldOwner ^8oc^LOa~2
FETCH NEXT FROM curObject INTO @Name, @Owner {qtc\O
END { .3
close curObject @Gn?8Ur%
deallocate curObject kuj12
GO KjwY'aYwr:
10、SQL SERVER中直接循环写入数据 '0_j{ig
declare @i int -Mi}yi
set @i=1 *iRm`)zC(
while @i<30 j
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begin hi3sOK*r;<
insert into test (userid) values(@i) O? Gl4_y
set @i=@i+1 <[y$D=n
end $]H=
小记存储过程中经常用到的本周,本月,本年函数 &Ky u@Tt
Dateadd(wk,datediff(wk,0,getdate()),-1) k Kp6
Dateadd(wk,datediff(wk,0,getdate()),6) bxhg*A
Dateadd(mm,datediff(mm,0,getdate()),0) yLgKS8b
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 2}Z4a\YX
Dateadd(yy,datediff(yy,0,getdate()),0) Y!=
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 29iIG
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上面的SQL代码只是一个时间段 gF,[u
Dateadd(wk,datediff(wk,0,getdate()),-1) {NY~JFM
Dateadd(wk,datediff(wk,0,getdate()),6) yXTK(<'
就是表示本周时间段. -q&7J'
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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: U%^eIXV|
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) I)XOAf$6
而在存储过程中 ;]&~D
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 2l)9Lz=;L
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6)
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