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。 o f
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一、基础 /+O8A}
1、说明:创建数据库 #q.G_-H4J@
CREATE DATABASE database-name 6*33k'=;F
2、说明:删除数据库 _O9H._E
drop database dbname Y_hRL&u3W
3、说明:备份sql server ld:alEo
--- 创建 备份数据的 device ~ O=| v/]
USE master ~(^*?(Z
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' G>>u#>0
--- 开始 备份 u@u.N2H.%
BACKUP DATABASE pubs TO testBack )uuEOF"w
4、说明:创建新表 TFDCo_>o
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) }h h^U^ia
根据已有的表创建新表: [=3tAPpzK
A:create table tab_new like tab_old (使用旧表创建新表) rss.F3dK
B:create table tab_new as select col1,col2... from tab_old definition only w*}yw"gP*0
5、说明:删除新表 [iy;}5XK
drop table tabname ATp 6-
6、说明:增加一个列 4 xzJql
Alter table tabname add column col type -8 =u{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。 q'@Ei4
7、说明:添加主键: Alter table tabname add primary key(col) eE`1;13;
说明:删除主键: Alter table tabname drop primary key(col) HTyF<K
8、说明:创建索引:create [unique] index idxname on tabname(col....) ~7WXjVZ
删除索引:drop index idxname \+Ln~\Sv
注:索引是不可更改的,想更改必须删除重新建。 zb}+ m#q
9、说明:创建视图:create view viewname as select statement Sb4PCt
删除视图:drop view viewname \OT)KVwO
10、说明:几个简单的基本的sql语句 7qK0!fk5
选择:select * from table1 where 范围 3N0X?* (x|
插入:insert into table1(field1,field2) values(value1,value2) kS#DKo
删除:delete from table1 where 范围 q)xl$*g
更新:update table1 set field1=value1 where 范围 nYt\e]3
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! H-KwkH`L4
排序:select * from table1 order by field1,field2 [desc] _D,f4.R
总数:select count as totalcount from table1 ,T*_mDVY
求和:select sum(field1) as sumvalue from table1 Zbh]SF{3F
平均:select avg(field1) as avgvalue from table1 #_\MD,(
最大:select max(field1) as maxvalue from table1 ^WW|AS
最小:select min(field1) as minvalue from table1 q }v04Yy,o
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11、说明:几个高级查询运算词 <i\zfa'6
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A: UNION 运算符 BI.k On=
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 D6)Cjc>a
B: EXCEPT 运算符 V0
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EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 + >gbZ-S
C: INTERSECT 运算符 yki51rOI*
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 3_*Xk.
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注:使用运算词的几个查询结果行必须是一致的。 Bx : So6:
12、说明:使用外连接 'BdmFKy1
A、left outer join: oT (:33$
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。 +[8Kl=]L
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 ]{2{:`s
B:right outer join: Q] yT
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。 0ij~e<
C:full outer join: X$|TN+Ub
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。 rjAkpAT
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二、提升 nB@iQxcz
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) m9<%v0r
法一:select * into b from a where 1<>1 #+Yp^6zg
法二:select top 0 * into b from a Ma=6kX]
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) h$7Fe +#I#
insert into b(a, b, c) select d,e,f from b; q?-3^z%u
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) ~d7Wjn$@
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 bqQO E4;
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. { .3
4、说明:子查询(表名1:a 表名2:b) y.*=Ww+
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) kuj12
5、说明:显示文章、提交人和最后回复时间 KjwY'aYwr:
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b '0_j{ig
6、说明:外连接查询(表名1:a 表名2:b) "^
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c *iRm`)zC(
7、说明:在线视图查询(表名1:a ) Ce5w0&VlS
select * from (SELECT a,b,c FROM a) T where t.a > 1; hi3sOK*r;<
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 Ns!3- Y
select * from table1 where time between time1 and time2 m,gy9$
select a,b,c, from table1 where a not between 数值1 and 数值2 V)1:LLRW
9、说明:in 的使用方法 zdjM%l);
select * from table1 where a [not] in ('值1','值2','值4','值6') {~p7*j^0
10、说明:两张关联表,删除主表中已经在副表中没有的信息 *)`kx
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) s\Pt,I@Y_
11、说明:四表联查问题: !(]dz~sM
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 ..... l'7Mw%6{
12、说明:日程安排提前五分钟提醒 *L;pc g8{
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ,P@/=I5
13、说明:一条sql 语句搞定数据库分页 $D/bU lFx
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 TI[UX16Tz1
14、说明:前10条记录 7moElh v
select top 10 * form table1 where 范围 .qIy7_^
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) 6_%]\37_Z
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) si^4<$Nr%j
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 Z`oaaO
(select a from tableA ) except (select a from tableB) except (select a from tableC) @k+%y'Y?
17、说明:随机取出10条数据 qF{DArc
select top 10 * from tablename order by newid() oGJ*Rn)Z
18、说明:随机选择记录 5qd_>UHp
select newid() XYb^Cs;
19、说明:删除重复记录 ksu}+i,a
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) #6N+5Yx_[
20、说明:列出数据库里所有的表名 AvrL9D
select name from sysobjects where type='U' y^d[( c
21、说明:列出表里的所有的 s^g.42?u
select name from syscolumns where id=object_id('TableName') .L^pMU+!^
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。 p2Dh3)&
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 <g3du~
显示结果: t/d' ,Khg
type vender pcs |k`f/*
电脑 A 1 Z&dr0w8
电脑 A 1 c/<Sa|'
光盘 B 2 $"sq4@N
光盘 A 2 R81{<q'%X
手机 B 3 Qst
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手机 C 3 crJ7pe9
23、说明:初始化表table1 RG l=7^M
TRUNCATE TABLE table1 p<=(GY-
24、说明:选择从10到15的记录 v@fe-T&0
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc $(@o$%d
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三、技巧 <G~}N
1、1=1,1=2的使用,在SQL语句组合时用的较多 &2io^AP
"where 1=1" 是表示选择全部 "where 1=2"全部不选, '?"t<$b
如: la\zaKC;>
if @strWhere !='' $hjP}- oUX
begin M&qh]v gC
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 'dIX=/RZ
end ;-KAUgL2
else aNE9LAms
begin PPoI>J
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' %@}o'=[
end \~@[QGKN
我们可以直接写成 'yPCZ`5H(
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere .3lGX`d{
2、收缩数据库 \7Gg2;TA6o
--重建索引 [=F>#8=
DBCC REINDEX gppBFS
DBCC INDEXDEFRAG bp]^EVx
--收缩数据和日志 Hp)X^O"
DBCC SHRINKDB n7IL7?!o
DBCC SHRINKFILE [G{rHSK5tQ
3、压缩数据库 CM%|pB/z
dbcc shrinkdatabase(dbname) r}/yi
4、转移数据库给新用户以已存在用户权限 V$/u
exec sp_change_users_login 'update_one','newname','oldname' Em e'Gk
go #XTY7,@P
5、检查备份集 [3O^0-:6E
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' $Wit17j
6、修复数据库 0U82f1ei
ALTER DATABASE [dvbbs] SET SINGLE_USER cGgM8
GO _ PXG AS
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK tcBC!_vF
GO =n@F$/h
ALTER DATABASE [dvbbs] SET MULTI_USER aO8ch
GO D
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7、日志清除 vkd[:CC
SET NOCOUNT ON dB@Wn!Y
DECLARE @LogicalFileName sysname, m#oh?@0}
@MaxMinutes INT, T-4/d5D[
@NewSize INT xGYSi5}z
USE tablename -- 要操作的数据库名 EY+/.=$x
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 XR*Q|4
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 4$yV%[j
@NewSize = 1 -- 你想设定的日志文件的大小(M) TZ?Os4+
-- Setup / initialize qqnclqkw&
DECLARE @OriginalSize int hi!L\yi
SELECT @OriginalSize = size m7$8k@r
FROM sysfiles A2m_q>>
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WHERE name = @LogicalFileName P^ptsZ%
SELECT 'Original Size of ' + db_name() + ' LOG is ' + wL 4ZW8_
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 2R^O,Vu*W
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' `J72+ RA
FROM sysfiles wgCvD
WHERE name = @LogicalFileName
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CREATE TABLE DummyTrans kTnOmAw
(DummyColumn char (8000) not null) >qR7'Q wP
DECLARE @Counter INT, vB[~pQ;Z
@StartTime DATETIME, *_`76`cz%X
@TruncLog VARCHAR(255) &^V~cJ
SELECT @StartTime = GETDATE(), _i5mC,OffN
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' NF6X- ,cd
DBCC SHRINKFILE (@LogicalFileName, @NewSize) yJ%t^ X_
EXEC (@TruncLog) <&4nOt
-- Wrap the log if necessary. 9|'
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired =EQJqj1T
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) i.3cj1
AND (@OriginalSize * 8 /1024) > @NewSize #@ 9)h
BEGIN -- Outer loop. !X^Hi=aV
SELECT @Counter = 0 :6XguU
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) KX!i\NHz
BEGIN -- update 6gXIt9B.h$
INSERT DummyTrans VALUES ('Fill Log') l0I}&,+
DELETE DummyTrans vt//)*(.$
SELECT @Counter = @Counter + 1 _`H.h6h
END K&*iw`
EXEC (@TruncLog) <"W?<VjO
END [+;qWfs B
SELECT 'Final Size of ' + db_name() + ' LOG is ' + {@?G 9UypA
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Ck: 9gn
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' X*i/A<Y`=
FROM sysfiles / /'Tck
WHERE name = @LogicalFileName :z]}ZZ
DROP TABLE DummyTrans ?AEd(_a!q
SET NOCOUNT OFF MhNFW'_
8、说明:更改某个表 j`O7=-
exec sp_changeobjectowner 'tablename','dbo' OB(pIzSe
9、存储更改全部表 + :V rip
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch /D<"wF }@J
@OldOwner as NVARCHAR(128), _5mc('
@NewOwner as NVARCHAR(128) P}0*{%jB
AS F*M|<E=
DECLARE @Name as NVARCHAR(128) moMYdArj
DECLARE @Owner as NVARCHAR(128) >&OUGu|
DECLARE @OwnerName as NVARCHAR(128) #/|75
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DECLARE curObject CURSOR FOR zrs<#8!Y_!
select 'Name' = name, (:5G#?6,
'Owner' = user_name(uid) 9qKzS<"h
from sysobjects [QT1Ju64
where user_name(uid)=@OldOwner `-_N@E1'>
order by name !YiuwFt
OPEN curObject
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FETCH NEXT FROM curObject INTO @Name, @Owner ;imRh'-V6
WHILE(@@FETCH_STATUS=0) f/,tgA
BEGIN 4e +~.5r@i
if @Owner=@OldOwner '0:i<`qv#g
begin 77V
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) 2jl)mL
exec sp_changeobjectowner @OwnerName, @NewOwner
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end ,vV]"f
-- select @name,@NewOwner,@OldOwner .x!T+`l>8I
FETCH NEXT FROM curObject INTO @Name, @Owner i(*I@ku
END IS BV%^la|
close curObject } VEq:^o.
deallocate curObject Zk&h:c
GO Rs*vm
10、SQL SERVER中直接循环写入数据 $<|ocUC7
declare @i int V
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set @i=1 ;#TaZN
while @i<30 l?/Y
begin \?D R
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insert into test (userid) values(@i) k6!4Zz_8
set @i=@i+1 (DDyK[t+VX
end C)Jn[/BD
小记存储过程中经常用到的本周,本月,本年函数 ME^,'&
Dateadd(wk,datediff(wk,0,getdate()),-1) EATu KLP\
Dateadd(wk,datediff(wk,0,getdate()),6) 3$VxRz)
Dateadd(mm,datediff(mm,0,getdate()),0) ,LZX@'5
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) =p@8z
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Dateadd(yy,datediff(yy,0,getdate()),0) !"Q}R p
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) _n"Ae?TP
上面的SQL代码只是一个时间段 fj>C@p
Dateadd(wk,datediff(wk,0,getdate()),-1) ymWgf6r<
Dateadd(wk,datediff(wk,0,getdate()),6) ;;Ds
就是表示本周时间段. {fV}gR2
下面的SQL的条件部分,就是查询时间段在本周范围内的: xY\0zQ
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) auHFir8f
而在存储过程中 /\Z J
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) e8}Ezy"^
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) MgJ36zM