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。 6UE(f@
z1!6%W_.
SjEdyN#
一、基础 !4rPv\
1、说明:创建数据库 G^(}a]>9
CREATE DATABASE database-name EHlytG}@
2、说明:删除数据库 CWO=0_>2
drop database dbname m ga6[E<
3、说明:备份sql server Se!)n;?7Sw
--- 创建 备份数据的 device Fn^C{p^
USE master GyC /_ntn
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' pX=,iOF[I
--- 开始 备份 Y?#i{ixX6n
BACKUP DATABASE pubs TO testBack [ "xn5lE
4、说明:创建新表 X[W]=yJJ
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ]=!P(z|
根据已有的表创建新表: k?VQi5M
A:create table tab_new like tab_old (使用旧表创建新表) V5D`eX9
B:create table tab_new as select col1,col2... from tab_old definition only LjdYsai-
5、说明:删除新表 kHJ96G
drop table tabname Q!M)xNl/
6、说明:增加一个列 *wV[TKaN
Alter table tabname add column col type )nu~9km3
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。 <TNk?df7
7、说明:添加主键: Alter table tabname add primary key(col) ^\:2}4Uj_
说明:删除主键: Alter table tabname drop primary key(col) jvzBh-!
8、说明:创建索引:create [unique] index idxname on tabname(col....) * \HRw +cL
删除索引:drop index idxname o;[bJ
Z\^x
注:索引是不可更改的,想更改必须删除重新建。 [k]|Qink
9、说明:创建视图:create view viewname as select statement nVD Xj
删除视图:drop view viewname Yn9j-`
10、说明:几个简单的基本的sql语句 A.Bk/N1G
选择:select * from table1 where 范围 Iwpbf Z
插入:insert into table1(field1,field2) values(value1,value2) Qeb}!k2A
删除:delete from table1 where 范围 xiyxrR;
更新:update table1 set field1=value1 where 范围 \O7J=6fn
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! XV'fW~j\
排序:select * from table1 order by field1,field2 [desc] yW.COWL=)
总数:select count as totalcount from table1 !~lW3
求和:select sum(field1) as sumvalue from table1 l>v{
平均:select avg(field1) as avgvalue from table1 JLb6C52
最大:select max(field1) as maxvalue from table1 x:t<ZG&Xwg
最小:select min(field1) as minvalue from table1 Ewo*yY>
(3*UPZv
+ySY>`1k~
yoqa@ V
11、说明:几个高级查询运算词 ODf4+& u
*(cU]NUH_
YYRT.U'
A: UNION 运算符 $gp!w8h
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。 "D*Wi7
B: EXCEPT 运算符 &B!%fd.'
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。 w5]l1}rl
C: INTERSECT 运算符 :k46S<RE
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。 %d: A`7x
注:使用运算词的几个查询结果行必须是一致的。 A2x;fgi
12、说明:使用外连接 |)@N-f:E
A、left outer join: -PAF p3w\y
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。 FoPginZ]J
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 %B EC]
h
B:right outer join: 9e<Zgr?N
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。 ][Y^-Ak1
C:full outer join: SvK1.NUa
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。 )Mzt3u
d^39t4
r@T| e
二、提升 EaS~`
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) S=gW(c2'
法一:select * into b from a where 1<>1 2w?G.pO#
法二:select top 0 * into b from a 9u wL{P&
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) U
|F>W~%
insert into b(a, b, c) select d,e,f from b; SZVV40w
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) "E*8h/4u
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 }sMW3'V
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. i#,1iVSG
4、说明:子查询(表名1:a 表名2:b) Q2C)tVK+
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) /BH.>R4`A
5、说明:显示文章、提交人和最后回复时间 ~,}s(`~
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b {Iy7.c8S
6、说明:外连接查询(表名1:a 表名2:b) ^i<}]c_|f
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 7tH]*T9e>
7、说明:在线视图查询(表名1:a ) I{dl% z73
select * from (SELECT a,b,c FROM a) T where t.a > 1; A|<;
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 |#TXE|#ux
select * from table1 where time between time1 and time2 $cK^23H/Fj
select a,b,c, from table1 where a not between 数值1 and 数值2 +0pW/4x
9、说明:in 的使用方法 PW_`qP:
select * from table1 where a [not] in ('值1','值2','值4','值6') i+~QDo(Pi
10、说明:两张关联表,删除主表中已经在副表中没有的信息 vmKTF!;
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) T2bnzIi
11、说明:四表联查问题: a'[)9:
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... X9'xn 0n;
12、说明:日程安排提前五分钟提醒 =|y|P80w
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 bNvAyKc-
13、说明:一条sql 语句搞定数据库分页 B-Y+F
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 'TEyP56
14、说明:前10条记录 R}J-nJlb
select top 10 * form table1 where 范围 ' yNPhI
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) 5fHYc0
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) .]Ybp2`"U
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 v#=ayWgk
(select a from tableA ) except (select a from tableB) except (select a from tableC) Ea`OT+#h(*
17、说明:随机取出10条数据 i
X/tt
select top 10 * from tablename order by newid() ",Wf uz
18、说明:随机选择记录 L_*L`!vQA"
select newid() \o9@[t>&2
19、说明:删除重复记录 {v+a!#{c7
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) i=Kvz4h
20、说明:列出数据库里所有的表名 ~t9$IB
select name from sysobjects where type='U' P,1exgq9
21、说明:列出表里的所有的 o5#,\Y[ g
select name from syscolumns where id=object_id('TableName') ~yN(-I1P
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。 ChIoR:y>
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 \r]('x3S
显示结果: Za\RM[Z!I
type vender pcs fH!=Zb_{8
电脑 A 1 H!JWc'(<$
电脑 A 1 EHWv3sR-
光盘 B 2 p#b{xK
光盘 A 2 -IvL+}K
手机 B 3 $i&\\QNn
手机 C 3 |!re8|JV_
23、说明:初始化表table1 \|!gPc%s
TRUNCATE TABLE table1 u'@Ely
24、说明:选择从10到15的记录 9}whWh
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 5}SXYA}
&^ceOV0+
<t6d)mJ%
m9g^ -X
三、技巧 =n
}Yqny
1、1=1,1=2的使用,在SQL语句组合时用的较多 W}k[slqZA
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ~\bHfiIDy
如: L` [F~$|
if @strWhere !='' *'^:S#=
begin %EB;1
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 0HPO"x3-O
end l-=e62I{=|
else 0(vdkC4\A
begin X0x_+b?
_
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' I:/4t^%
end ;5RIwD
我们可以直接写成 ;7
"Y?*{
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere oF&IC
j0
2、收缩数据库 VLd=" ~
--重建索引 %jgg59
DBCC REINDEX 3AP YO
DBCC INDEXDEFRAG 6+#,=!hF{
--收缩数据和日志 tAt;bYjb\
DBCC SHRINKDB Eb7}$Ji\
DBCC SHRINKFILE >;.*
3、压缩数据库 MZiF];OY
dbcc shrinkdatabase(dbname) |bvGYsn_#=
4、转移数据库给新用户以已存在用户权限 J<-Fua^
exec sp_change_users_login 'update_one','newname','oldname' WV~SL/k|
go ~6fRS2u
5、检查备份集 cB36p&%
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' DsG !S*
6、修复数据库 Vdy\4 nu(
ALTER DATABASE [dvbbs] SET SINGLE_USER ,QL(i\
GO s|p(KWo2U
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Wlxk
GO +ks$UvtY
ALTER DATABASE [dvbbs] SET MULTI_USER xx}'l:}2]
GO L.Vq1RU\"
7、日志清除 6fQ*X~| p
SET NOCOUNT ON Q^kMCrp
DECLARE @LogicalFileName sysname, ~:s!].H
@MaxMinutes INT, ~s0P FS7
@NewSize INT L]a|vp
USE tablename -- 要操作的数据库名 %SFw~%@3&~
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 }(rzH}X@
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Y/!0Q6<[2Y
@NewSize = 1 -- 你想设定的日志文件的大小(M) x6~Fb~aP
-- Setup / initialize # m_\1&g
DECLARE @OriginalSize int t3M0La&
SELECT @OriginalSize = size KD9Ca $-
FROM sysfiles B4 <_"0
WHERE name = @LogicalFileName OT"lP(,
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ]:Wb1
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + R=QM;
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' H;X~<WN&AW
FROM sysfiles G)K9la<p
WHERE name = @LogicalFileName !zl/0o
CREATE TABLE DummyTrans "9.6\Y\*
(DummyColumn char (8000) not null) ~v,!n/('
DECLARE @Counter INT, E'fX&[
@StartTime DATETIME, @)06\h
@TruncLog VARCHAR(255) Q,O]x#
SELECT @StartTime = GETDATE(), <6gU2@1
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' hiT9H5 6>
DBCC SHRINKFILE (@LogicalFileName, @NewSize) U bpg92
EXEC (@TruncLog) (''$'5~
-- Wrap the log if necessary. MQhYJ01i
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired UfO'.8*v
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) WoJ]@Me8
AND (@OriginalSize * 8 /1024) > @NewSize kv[OW"8t
BEGIN -- Outer loop. )
+*@AME
SELECT @Counter = 0 8g&uE*7N
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) KS8\F0q
BEGIN -- update _GRv
INSERT DummyTrans VALUES ('Fill Log') 7?*~oVZW
DELETE DummyTrans %9cqJ]S
SELECT @Counter = @Counter + 1 r]xdhR5
END ;Ce 2d+K
EXEC (@TruncLog) _6|
/P7"
END Ab/v_mA;
SELECT 'Final Size of ' + db_name() + ' LOG is ' + C} |O#"t^\
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + I(F1S,7
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ]eORw$f
FROM sysfiles T`j
WHERE name = @LogicalFileName >2*6qx>V
DROP TABLE DummyTrans xXl$Mp7
SET NOCOUNT OFF 1Q3%!~<\s
8、说明:更改某个表 {_+>"esc
exec sp_changeobjectowner 'tablename','dbo' cM|af#o
9、存储更改全部表 G`&'Bt{Z*
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch NN?Bi=&9
@OldOwner as NVARCHAR(128), `,<>){c|
@NewOwner as NVARCHAR(128) !<JG&9ODP
AS ^$3w&$K*
DECLARE @Name as NVARCHAR(128) HP1X\h!Ke
DECLARE @Owner as NVARCHAR(128) h%4~0
DECLARE @OwnerName as NVARCHAR(128) =r=^bNO
DECLARE curObject CURSOR FOR hnlU,p&y3
select 'Name' = name, #IcT
@(
'Owner' = user_name(uid) s#4))yUR6Z
from sysobjects )3d:S*ly
where user_name(uid)=@OldOwner mvxc[
order by name %@)U/G6s}
OPEN curObject axt6u)4%7:
FETCH NEXT FROM curObject INTO @Name, @Owner k0Oc,P`'*
WHILE(@@FETCH_STATUS=0) Zm?G'06
BEGIN JT}dor
if @Owner=@OldOwner h?M'7Lti
begin :z}~U3,JE
set @OwnerName = @OldOwner + '.' + rtrim(@Name) !!\4'Q[
exec sp_changeobjectowner @OwnerName, @NewOwner B]CS2LEqh
end o%QhV6(F
-- select @name,@NewOwner,@OldOwner *m2d#f
FETCH NEXT FROM curObject INTO @Name, @Owner WcQZFtW
END #<^/yoH7C6
close curObject uugzIV)
deallocate curObject .oB'ttF1
GO \q>e1-
10、SQL SERVER中直接循环写入数据 4c9-[KKCV
declare @i int l93Q"*_
set @i=1 c'm-XL_La
while @i<30 cJ1{2R
begin ,(5dQ` hA0
insert into test (userid) values(@i) as\)S?0`.
set @i=@i+1 M]pel\{M
end X,Q6
小记存储过程中经常用到的本周,本月,本年函数 `RL(N4H
Dateadd(wk,datediff(wk,0,getdate()),-1) `-E.n'+
Dateadd(wk,datediff(wk,0,getdate()),6) gDjd{+LUo
Dateadd(mm,datediff(mm,0,getdate()),0) @vDgpb@TM
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) UwzE'#Q-
Dateadd(yy,datediff(yy,0,getdate()),0) F\YcSDM
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) cPa 0n4
上面的SQL代码只是一个时间段 ACMpm~C8Gu
Dateadd(wk,datediff(wk,0,getdate()),-1) 8O}A/*1FJ
Dateadd(wk,datediff(wk,0,getdate()),6) -+Awm{X_@
就是表示本周时间段. ;nHo%`Zt
下面的SQL的条件部分,就是查询时间段在本周范围内的: 8M5!5Jzv
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) O=9V X
而在存储过程中 p>w~T#17
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) WL*W=(
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) $e^ :d