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。 8isQL
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一、基础 ph~BxK )i6
1、说明:创建数据库 l hST%3Ld
CREATE DATABASE database-name ;d
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2、说明:删除数据库 /QQjb4S}
drop database dbname nYe:$t3F=
3、说明:备份sql server B>@l(e)b
--- 创建 备份数据的 device R`B} T<*
USE master `Jh<8~1
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' PKQ.gPu6*@
--- 开始 备份 6Cfsh<]b
BACKUP DATABASE pubs TO testBack (6b0rqPF
4、说明:创建新表 A4rkwM
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) N|3#pHm@
根据已有的表创建新表: rinTB|5
A:create table tab_new like tab_old (使用旧表创建新表) {qOqtkj
B:create table tab_new as select col1,col2... from tab_old definition only OL_jU2,fv
5、说明:删除新表 lQy-&d|=#^
drop table tabname ) $0>L5d:
6、说明:增加一个列 +r&:c[
Alter table tabname add column col type WdB\n/BWB
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 JoZSp"R
7、说明:添加主键: Alter table tabname add primary key(col) JpxQS~VX
说明:删除主键: Alter table tabname drop primary key(col) 12;YxW>[
8、说明:创建索引:create [unique] index idxname on tabname(col....) D4uAwmc
删除索引:drop index idxname &gUa^5'#
注:索引是不可更改的,想更改必须删除重新建。 iio-RT?!
9、说明:创建视图:create view viewname as select statement z 7+>G/o
删除视图:drop view viewname \L`x![$~q
10、说明:几个简单的基本的sql语句 \jmZt*c
选择:select * from table1 where 范围 ]2
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插入:insert into table1(field1,field2) values(value1,value2) K}2G4*8S_G
删除:delete from table1 where 范围 [HL>Lp&A?
更新:update table1 set field1=value1 where 范围 ) .KMZ]
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! sZ;Gb^{Z
排序:select * from table1 order by field1,field2 [desc] ).A9>^6?{
总数:select count as totalcount from table1 i"pOYZW1
求和:select sum(field1) as sumvalue from table1 i0J`{PbI
平均:select avg(field1) as avgvalue from table1 ^P*-bV4
最大:select max(field1) as maxvalue from table1 S_ UAz
最小:select min(field1) as minvalue from table1 d={o|Mf
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11、说明:几个高级查询运算词 *M_^I)*L
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A: UNION 运算符 H8=:LF
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。 7[UD;&\k
B: EXCEPT 运算符 &`m$Zzl;
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。 WW>m`RU`
C: INTERSECT 运算符 7#NHPn
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。 t\TxK7i
注:使用运算词的几个查询结果行必须是一致的。 WuFBt=%
12、说明:使用外连接 B2'TRXIm1U
A、left outer join: p\9}}t7n
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。 FOsxId[f9
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 sriDta?Cz
B:right outer join: FSAX,Y
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。 m l@%H
C:full outer join: vxLr034
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。 4>a(!ht
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二、提升 72.Msnn
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) PxGw5:
法一:select * into b from a where 1<>1 6,MQT,F
法二:select top 0 * into b from a #f HnM+
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) "v(pluN|
insert into b(a, b, c) select d,e,f from b; o4J@M{xb_
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) /&_q"y9
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 +."cbqGP_q
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. E^br-{|{
4、说明:子查询(表名1:a 表名2:b) 41s\^'^&
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) EtaKo}!A}
5、说明:显示文章、提交人和最后回复时间 &[_@f#
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ] $r].,&
6、说明:外连接查询(表名1:a 表名2:b) jD}h`(bE
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c WSN^iDS
7、说明:在线视图查询(表名1:a ) t|hc`|
select * from (SELECT a,b,c FROM a) T where t.a > 1; x[&<e<6
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 NQX?&9L`r
select * from table1 where time between time1 and time2 !H[01
select a,b,c, from table1 where a not between 数值1 and 数值2 (Y8LyY
9、说明:in 的使用方法 C"B'Dj
select * from table1 where a [not] in ('值1','值2','值4','值6') R=&-nC5e
10、说明:两张关联表,删除主表中已经在副表中没有的信息 \AH5zdK
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 0t}v@-abU
11、说明:四表联查问题: ,+4T7 U R
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 ..... _X mxBtk9f
12、说明:日程安排提前五分钟提醒 "bF52lLu
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 M\
13、说明:一条sql 语句搞定数据库分页 II| ;_j
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 ,aGIq. *v
14、说明:前10条记录 .P/0`A{&
select top 10 * form table1 where 范围 }^$1<GT
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.) $/tj<++W
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) a:`<=^:4,
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 v}a{nU'
(select a from tableA ) except (select a from tableB) except (select a from tableC) T!B\ixt6
17、说明:随机取出10条数据 Q"nw.FjUG
select top 10 * from tablename order by newid() n%#3xoa
18、说明:随机选择记录 !<HMMf,-D
select newid() 4%w<Ekd
19、说明:删除重复记录 Mj6,VD9L
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) -N wic|
20、说明:列出数据库里所有的表名 yiI
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select name from sysobjects where type='U' (=;'>*L(
21、说明:列出表里的所有的 /|i*'6*
select name from syscolumns where id=object_id('TableName') .5o~^
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 AWx@Z7\z"g
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type %;v~MC@
显示结果: *fIn<Cc
type vender pcs #k|f>D4
电脑 A 1 u_
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电脑 A 1 zIu/!aw
光盘 B 2 Qg~w 3~
光盘 A 2 n8=Dzv0
手机 B 3 D"$Y, d
手机 C 3 4K~=l%l
23、说明:初始化表table1 a^@.C5
TRUNCATE TABLE table1 d=%NFCIV
24、说明:选择从10到15的记录 u/6if9B
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ^uN[rHZ*u
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三、技巧 fuv{2[NV
1、1=1,1=2的使用,在SQL语句组合时用的较多 3~Fag1Hp
"where 1=1" 是表示选择全部 "where 1=2"全部不选, WQ[nK5#
如: .BBJhXtrdu
if @strWhere !='' t,JX6ni
begin XX%K_p`&Z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere FGHCHSqLq
end ~5%3]
else d4 \
begin |C z7_Rn
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' *8?2+)5"
end =Q<7[
我们可以直接写成 LOcZadr
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere cl`Wl/Q#
2、收缩数据库 p<L{e~{!7f
--重建索引 _v 0iH
DBCC REINDEX [1kQ-Ko`
DBCC INDEXDEFRAG IJ2'
--收缩数据和日志 |TMn
DBCC SHRINKDB W-#DEU 7_
DBCC SHRINKFILE ='b)6R
3、压缩数据库 RIXeV*ix
dbcc shrinkdatabase(dbname) T5zS3O
4、转移数据库给新用户以已存在用户权限
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exec sp_change_users_login 'update_one','newname','oldname' >wmHCOL:
go 6JZ>&HA
5、检查备份集 ,m?V3xvq
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' $ MH;v_'a
6、修复数据库 iD|~$<9o
ALTER DATABASE [dvbbs] SET SINGLE_USER qna!j|90Lp
GO kOD=H-vSi
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK [niFJIsc
GO |rk.t g9
ALTER DATABASE [dvbbs] SET MULTI_USER *6AV^^
GO 9G
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7、日志清除 n8; p]{
SET NOCOUNT ON 1-?i*C
DECLARE @LogicalFileName sysname, DoQ^caa@
@MaxMinutes INT, g_c@Kyf
@NewSize INT uBt
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USE tablename -- 要操作的数据库名 o^X3YaS)
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 :E6*m\X!3
@MaxMinutes = 10, -- Limit on time allowed to wrap log. H i8V=+
@NewSize = 1 -- 你想设定的日志文件的大小(M) ?.<
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-- Setup / initialize J(d+EjC
DECLARE @OriginalSize int 3 5.&!4}
SELECT @OriginalSize = size K 'l-6JY-
FROM sysfiles j]kgdAq>
WHERE name = @LogicalFileName gdTW
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + uCB9;+ Hjw
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + %?].(
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' B<r0y
FROM sysfiles ef '?O
WHERE name = @LogicalFileName NO[A00m|OL
CREATE TABLE DummyTrans Rh~b,"
(DummyColumn char (8000) not null) ~8nR3ki
DECLARE @Counter INT, )u{]rb[
@StartTime DATETIME, X\Zan$oi
@TruncLog VARCHAR(255) ynM~&]fk#k
SELECT @StartTime = GETDATE(), tkHmH/'7
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' _ncBq;j{
DBCC SHRINKFILE (@LogicalFileName, @NewSize) IKP_%R8.
EXEC (@TruncLog) "Tser*i )
-- Wrap the log if necessary. B7'#8heDh
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired *w*K&$g
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) jnOnV1I"
AND (@OriginalSize * 8 /1024) > @NewSize =Mwuhk|*
BEGIN -- Outer loop. m85ZcyW1T
SELECT @Counter = 0 RN)XIf$@_
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) lmHQ"z 3G
BEGIN -- update H}~K51
INSERT DummyTrans VALUES ('Fill Log') 0~BaQ,
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DELETE DummyTrans P-2DBNB7
SELECT @Counter = @Counter + 1 Yz0fOX
END td%J.&K_*'
EXEC (@TruncLog) k;cX,*DIn
END zuN(~>YH
SELECT 'Final Size of ' + db_name() + ' LOG is ' + \\:%++}J
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + <t(H+ykh
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' c]x-mj =
FROM sysfiles -JEPh!oTt
WHERE name = @LogicalFileName \K\eq>@6
DROP TABLE DummyTrans Q`8-|(ngw
SET NOCOUNT OFF $Xt""mlQ
8、说明:更改某个表 !5De?OXe
exec sp_changeobjectowner 'tablename','dbo' |g}r
9、存储更改全部表 !c)F;
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch l2n`fZL
@OldOwner as NVARCHAR(128), PQlA(v+S
@NewOwner as NVARCHAR(128) ',`Qx{tQ)
AS J#Y0R"fo
DECLARE @Name as NVARCHAR(128) 8Pd9&/Y
DECLARE @Owner as NVARCHAR(128) W*S4gPGM
DECLARE @OwnerName as NVARCHAR(128) "!Ph
DECLARE curObject CURSOR FOR >2>/
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select 'Name' = name, ~fD\=- S1
'Owner' = user_name(uid) o?/H<k\5
from sysobjects T;B FO5G@
where user_name(uid)=@OldOwner M.dX;iM<
order by name w?u3e+
OPEN curObject ?`xF>P]M
FETCH NEXT FROM curObject INTO @Name, @Owner
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WHILE(@@FETCH_STATUS=0) l:@=9Fp>
BEGIN 6;Z`9PGp
if @Owner=@OldOwner LYYz=oZOE!
begin |X1axRO
set @OwnerName = @OldOwner + '.' + rtrim(@Name) +2:HgW
exec sp_changeobjectowner @OwnerName, @NewOwner /"`hz6rIv
end ?0dmw?i
-- select @name,@NewOwner,@OldOwner BJ3<"D{.*4
FETCH NEXT FROM curObject INTO @Name, @Owner 1qAE)8ie
END o9|
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close curObject u=L Dfn
deallocate curObject %`s#p` Ol1
GO kw z6SObQ
10、SQL SERVER中直接循环写入数据 \Cq4r4'
declare @i int d`V.i6u
set @i=1 >G!=lLyR
while @i<30 {Lv"wec*x
begin $2*_7_Qb
insert into test (userid) values(@i) :!t4.ko
set @i=@i+1 Bt")RG
end {ly <%Q7j
小记存储过程中经常用到的本周,本月,本年函数 I:DAn!N-A*
Dateadd(wk,datediff(wk,0,getdate()),-1) XgVhb<l_
Dateadd(wk,datediff(wk,0,getdate()),6) `'iO+/;GY
Dateadd(mm,datediff(mm,0,getdate()),0) arR<!y7
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) gp$]0~[tO
Dateadd(yy,datediff(yy,0,getdate()),0) 2K/t[.8
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) v9@_DlV\
上面的SQL代码只是一个时间段 \6 J Y#%
Dateadd(wk,datediff(wk,0,getdate()),-1) sbVEA
Dateadd(wk,datediff(wk,0,getdate()),6) pLF,rOb
就是表示本周时间段.
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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: Kp7)my
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 8q]"CFpa
而在存储过程中 a"Iu!$&N
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) : i.5
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) "h1ek*(?<