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。 G!54 e
or u.a
A}b<Lg
一、基础 tF)aNtX4^
1、说明:创建数据库 =^P<D&%q
CREATE DATABASE database-name =J,aB p
2、说明:删除数据库 !m$OI:rr
drop database dbname FxC@KZG
3、说明:备份sql server 6M"]p
--- 创建 备份数据的 device ti'a^(
USE master Xv'M\T}6C+
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' IN!m
--- 开始 备份 #{ M$%l>
BACKUP DATABASE pubs TO testBack 5w`v
3o
4、说明:创建新表 ()vxTTa
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) i+&*W{Re
根据已有的表创建新表: f;6a4<bz
A:create table tab_new like tab_old (使用旧表创建新表) Z8Fbx+~"
B:create table tab_new as select col1,col2... from tab_old definition only Q^8C*ekfg!
5、说明:删除新表 MOyQ4<_
drop table tabname Z-b^{uP
6、说明:增加一个列 xv9Z~JwH
Alter table tabname add column col type a Kb2:1EQ
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。 vcAs!ls+
7、说明:添加主键: Alter table tabname add primary key(col) Gu&?Gn oc
说明:删除主键: Alter table tabname drop primary key(col) <UG}P \N
8、说明:创建索引:create [unique] index idxname on tabname(col....) UR?[ba_h
删除索引:drop index idxname u(?
注:索引是不可更改的,想更改必须删除重新建。 )5Kzq6.
9、说明:创建视图:create view viewname as select statement >(u =/pp=:
删除视图:drop view viewname X#(?V[F]
10、说明:几个简单的基本的sql语句 ]]+wDhxH
选择:select * from table1 where 范围 /+Xv(B
插入:insert into table1(field1,field2) values(value1,value2) b IcLMG
s
删除:delete from table1 where 范围 9xC,i
)
更新:update table1 set field1=value1 where 范围 )oa6;=go
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! C]-Z+9Vvv
排序:select * from table1 order by field1,field2 [desc] F`U%xn,
总数:select count as totalcount from table1 xF5q=%n
求和:select sum(field1) as sumvalue from table1 T<DQi
平均:select avg(field1) as avgvalue from table1 $\$5::}r
最大:select max(field1) as maxvalue from table1 [z`U9J
最小:select min(field1) as minvalue from table1 on+
c*#
vj^vzFb K
AU$W=Z*
gec<5Ewg
11、说明:几个高级查询运算词 wCvtw[6
k#E D#']N
v-X1if1%
A: UNION 运算符 Ip(
IGR"
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。 "Sc_E}q|e
B: EXCEPT 运算符 Ta%{Wa\U9z
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。 uE-~7Q(@
C: INTERSECT 运算符 J-ACV(z=q
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。 Tl %#N"
注:使用运算词的几个查询结果行必须是一致的。 !Z,h5u\.w
12、说明:使用外连接 v$w!hYsQ
A、left outer join: h2!We#
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。 \Zqgr/.w/
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 ;4Y@xS2M
B:right outer join: }f<.07
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。 ykxjT@[
C:full outer join: ]0zXpMNI
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。 ?z171X0
GNqw]@'Yf
~9p*zC3M
二、提升 Ytc
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) D&/(Avx.
法一:select * into b from a where 1<>1 ^~0\d;l_
法二:select top 0 * into b from a v1QE|@
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) fnG&29x
insert into b(a, b, c) select d,e,f from b; UC;_}>
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) b"t!nfgo
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 $VhUZGuG>
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ,;'9PsIS^
4、说明:子查询(表名1:a 表名2:b) v}IkY
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) ngcXS2S_
5、说明:显示文章、提交人和最后回复时间 _LFZ 0
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b !!b5vzyve
6、说明:外连接查询(表名1:a 表名2:b) Ni'vz7j
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%xJ[
7、说明:在线视图查询(表名1:a ) c</d1x T
select * from (SELECT a,b,c FROM a) T where t.a > 1; OnC|9
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 ]ZelB,7q
select * from table1 where time between time1 and time2 _0 USe
select a,b,c, from table1 where a not between 数值1 and 数值2 (01M 0b#
9、说明:in 的使用方法 ~C{d2i
select * from table1 where a [not] in ('值1','值2','值4','值6') >0=` 3X|Y7
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ?0WJB[/
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) <bWhTNOb
11、说明:四表联查问题: Q_euNoA0
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 ..... vAbMU
12、说明:日程安排提前五分钟提醒 =GTltFqI1
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 GNA:|x
13、说明:一条sql 语句搞定数据库分页 Rgw\qOb
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 H*!j\|v0
14、说明:前10条记录 =4"D8UaHr
select top 10 * form table1 where 范围 Bl2y~fCA
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.)
5 .
5
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) @>_`g=
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 h )"PPI
(select a from tableA ) except (select a from tableB) except (select a from tableC) @H"~/ m_o
17、说明:随机取出10条数据 3 ~0Z.!O
select top 10 * from tablename order by newid() a=&a)FR
18、说明:随机选择记录 j` 9pZAF
select newid() '`#2'MXG
19、说明:删除重复记录 ~&[Wqn@MZ
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) n|Iy
20、说明:列出数据库里所有的表名 3<1Uq3Pa
select name from sysobjects where type='U' w-2p'u['Z
21、说明:列出表里的所有的 ns9iTU)
select name from syscolumns where id=object_id('TableName') znw\Dn?g
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。 @Nn9-#iW
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 Pdmfn8I]%
显示结果: :[m;#b
type vender pcs rJ4O_a5/
电脑 A 1 Ig t:M[
/
电脑 A 1
fD
光盘 B 2 YQvN;W
光盘 A 2 y~w2^VN=
手机 B 3 ZMy0iQ@
手机 C 3 d_BECx<\
23、说明:初始化表table1 YgNt>4K
TRUNCATE TABLE table1 ^]3Y11sI
24、说明:选择从10到15的记录 sWP5=t(i+9
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Yj|Oy
,`v)nwP
zdrCr0Rx,
&*B=5W;6^u
三、技巧 2--"@@
1、1=1,1=2的使用,在SQL语句组合时用的较多 3k py3z[%
"where 1=1" 是表示选择全部 "where 1=2"全部不选, jxU1u"WU
如: %Wkvo-rOq
if @strWhere !='' ;t{Ew+s
begin dFFJw[$8w
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Q<3=s6@T
end Mdsn"Y V
else @tWyc%t
begin cJd~UQ<k
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' t8DySFT
end iUJqAi1o
我们可以直接写成 {5QIQ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere IqJ7'X
2、收缩数据库 uIvy1h9m
--重建索引 0tv"tA;
DBCC REINDEX ce{(5IC
DBCC INDEXDEFRAG m_\w)
--收缩数据和日志 SCs@Q
DBCC SHRINKDB 97lM*7h;
DBCC SHRINKFILE 8Eyi`~cAiH
3、压缩数据库 1O>wXq7q
dbcc shrinkdatabase(dbname) Xp@8vu
4、转移数据库给新用户以已存在用户权限 A9'
[x7N
exec sp_change_users_login 'update_one','newname','oldname' uo;aC$US
go fhw.A5Ck
5、检查备份集 aN?{MA\
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ~CgKU8
6、修复数据库 {L5!_]6
ALTER DATABASE [dvbbs] SET SINGLE_USER y.AVH`_u
GO \Z-T)7S
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK kRo
dC(f
@
GO 4NT zK
ALTER DATABASE [dvbbs] SET MULTI_USER OvqCuX
GO G=W!$(:
7、日志清除 ~s{yh-B
SET NOCOUNT ON ^m.QW*
DECLARE @LogicalFileName sysname, WeNx9+2=Z
@MaxMinutes INT, s+&Ts|c#
@NewSize INT e>vV8a\
USE tablename -- 要操作的数据库名 +e?mKLw14
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 eR PmN
@MaxMinutes = 10, -- Limit on time allowed to wrap log. p%toD{$
@NewSize = 1 -- 你想设定的日志文件的大小(M) SQhk)S
-- Setup / initialize wDswK "T
DECLARE @OriginalSize int T+ey>[
SELECT @OriginalSize = size ,ef"S
r
FROM sysfiles }'mVD^<+
WHERE name = @LogicalFileName WJbdsPs
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ?K%&N99c!
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + /fC@T
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' =+9.X8SP
FROM sysfiles KKP}fN
WHERE name = @LogicalFileName f_a.BTtNO
CREATE TABLE DummyTrans Pj9n`LwM
(DummyColumn char (8000) not null) 8.FBgZh*
DECLARE @Counter INT, /HbxY
@StartTime DATETIME, $zS0]@Dj
@TruncLog VARCHAR(255) 86igP
SELECT @StartTime = GETDATE(), ~CiVLSH=
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' }`#OA]NZ
DBCC SHRINKFILE (@LogicalFileName, @NewSize) dR~4*59Bg
EXEC (@TruncLog) qplz !=
-- Wrap the log if necessary. N=FU>qbz
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired p?(w! O
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) l*_%K}%?V
AND (@OriginalSize * 8 /1024) > @NewSize y^7;I-
BEGIN -- Outer loop. SQ!wq
SELECT @Counter = 0 B7r={P!0
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) gZ%wmY
BEGIN -- update ,_;+H*H>"
INSERT DummyTrans VALUES ('Fill Log') iJ.P&T9
DELETE DummyTrans `X[L62D
SELECT @Counter = @Counter + 1 R|aA6} /I
END n!=%MgF'*p
EXEC (@TruncLog) PhF.\Wb
END ReE-I/n8f
SELECT 'Final Size of ' + db_name() + ' LOG is ' + zK`fX
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 5N
"fD{v{
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' XOgl>1O
FROM sysfiles V^fSrW]
WHERE name = @LogicalFileName pwo5Ij,~q
DROP TABLE DummyTrans ?z3c$}
SET NOCOUNT OFF KNT(lA0s
8、说明:更改某个表 a)J3=Z-
exec sp_changeobjectowner 'tablename','dbo' 9l).L L
9、存储更改全部表 v
Yt-Nx
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch "{>I5<:t
@OldOwner as NVARCHAR(128), EH))%LY1y
@NewOwner as NVARCHAR(128) ?w'a^+H
AS Lt ;!q b.
DECLARE @Name as NVARCHAR(128) bl@0+NiM
DECLARE @Owner as NVARCHAR(128) 59K%bz5t
DECLARE @OwnerName as NVARCHAR(128) @V{s'V
DECLARE curObject CURSOR FOR
Td tn-
select 'Name' = name, Y@x }b{3
'Owner' = user_name(uid) jO
xH'1I
from sysobjects n5CjwLgu\b
where user_name(uid)=@OldOwner MG ,exN
@
order by name #?%akQ+w
OPEN curObject KWtLrZ(j
FETCH NEXT FROM curObject INTO @Name, @Owner .w5#V|
WHILE(@@FETCH_STATUS=0) k8fvg4
BEGIN o=i)s2
if @Owner=@OldOwner + E8\g
begin (2J_Y*N~>
set @OwnerName = @OldOwner + '.' + rtrim(@Name) n';"c;Ye)
exec sp_changeobjectowner @OwnerName, @NewOwner -L e:%q2
end FlJ(V
-- select @name,@NewOwner,@OldOwner t}m6];
FETCH NEXT FROM curObject INTO @Name, @Owner ZqKUz5M4
END XVwaX2=L
close curObject XQCu\\>;
deallocate curObject 7^$PauAv
GO 2>~{.4PI
10、SQL SERVER中直接循环写入数据 =
7U^pT
declare @i int w?_y;&sbR
set @i=1 tY$
.(2Ua
while @i<30 "0x"Xw#I
begin 9_Tk8L#
insert into test (userid) values(@i) 1Xy{&Ut\
set @i=@i+1 qh}M!p2
end P(?i>F7s
小记存储过程中经常用到的本周,本月,本年函数 g7*c wu
Dateadd(wk,datediff(wk,0,getdate()),-1) Z}bUvr XP
Dateadd(wk,datediff(wk,0,getdate()),6) ECHl9;
+
Dateadd(mm,datediff(mm,0,getdate()),0) |rJ1/T.9
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) TAz#e
Dateadd(yy,datediff(yy,0,getdate()),0) _Eq*
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) `P1jg$(eA
上面的SQL代码只是一个时间段 2yqm$i9C
Dateadd(wk,datediff(wk,0,getdate()),-1) AWlR" p2
Dateadd(wk,datediff(wk,0,getdate()),6) [@D+kL*>
就是表示本周时间段. WK7=z3mu
下面的SQL的条件部分,就是查询时间段在本周范围内的: U9:?d>7
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ,EPs>#d
而在存储过程中 sO7$b@"u.
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) @91Q=S
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) #6g-{OBv