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。 LAfv1
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一、基础 +ZxG<1&
1、说明:创建数据库 v9K{oB
CREATE DATABASE database-name 1xF<c<
2、说明:删除数据库 c<J/I_!
drop database dbname .<|.nK` 6
3、说明:备份sql server ("$ ,FRTQ:
--- 创建 备份数据的 device Z_Z; g]|!
USE master h,WF'X+
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Lm}J&^>
--- 开始 备份 >:yU bo)
BACKUP DATABASE pubs TO testBack %.+#e
4、说明:创建新表 -F+dmI,1$
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ON~K(O2g(
根据已有的表创建新表: k yI -nE
A:create table tab_new like tab_old (使用旧表创建新表) /"*eMe!=
B:create table tab_new as select col1,col2... from tab_old definition only 3vK,vu q
5、说明:删除新表 si|DxDx
drop table tabname +bv-! rf
6、说明:增加一个列 x!@P|c1nKC
Alter table tabname add column col type Z(=UZI?
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。 /5Zt4&r
7、说明:添加主键: Alter table tabname add primary key(col) {~RS$ |
说明:删除主键: Alter table tabname drop primary key(col) -B l!s^-'
8、说明:创建索引:create [unique] index idxname on tabname(col....) Q
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删除索引:drop index idxname fqcFfz6?x
注:索引是不可更改的,想更改必须删除重新建。 PfKF!/c
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9、说明:创建视图:create view viewname as select statement u:FFZ
删除视图:drop view viewname ~-.^eT kP
10、说明:几个简单的基本的sql语句 +~~&FO2
选择:select * from table1 where 范围 |{G GATni
插入:insert into table1(field1,field2) values(value1,value2) JO `KNI
删除:delete from table1 where 范围 k-uwK-B}v+
更新:update table1 set field1=value1 where 范围 ZLRAiL
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! S`qa_yI)Ed
排序:select * from table1 order by field1,field2 [desc] Ct)l0J\XH
总数:select count as totalcount from table1 2UF
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求和:select sum(field1) as sumvalue from table1 .h;PMY+
平均:select avg(field1) as avgvalue from table1 ;F:~HrxT}
最大:select max(field1) as maxvalue from table1 :jc
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最小:select min(field1) as minvalue from table1 AM ZWPU
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11、说明:几个高级查询运算词 ]U8VU
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A: UNION 运算符 \~:Uj~
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。 :+m8~n$/
B: EXCEPT 运算符 pRAdo="
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 +?!x;qS^
C: INTERSECT 运算符 fuQb h
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 ]^j'2nJv0
注:使用运算词的几个查询结果行必须是一致的。 ~baVS-v
12、说明:使用外连接 y[W<vb+F
A、left outer join: OZ/!=;
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 EMV<PshW=
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c [9:'v@Ph
B:right outer join: D_HE!fl
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 .=nx5yz
C:full outer join: .Kn)sD1
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 Q^iE,_Zq
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二、提升 c~1X/,biA
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) l|O)B #
法一:select * into b from a where 1<>1 uP:Y[$O
法二:select top 0 * into b from a QX'EMyK$
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) F>0[v|LG
insert into b(a, b, c) select d,e,f from b; *7ggw[~
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) Kf.G'v46
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 |9;6Cp
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ,EAf/2C
4、说明:子查询(表名1:a 表名2:b) !&3iZQGWv
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) ~is$Onf99#
5、说明:显示文章、提交人和最后回复时间 q:y_#r"_y
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b /lC&'h T
6、说明:外连接查询(表名1:a 表名2:b) sUfYEVjr
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c }[[
7、说明:在线视图查询(表名1:a ) vu&%e\gM
select * from (SELECT a,b,c FROM a) T where t.a > 1; Zj*kHjn"
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 L+c7.l.yT
select * from table1 where time between time1 and time2 &!y7PWHJ
select a,b,c, from table1 where a not between 数值1 and 数值2 :< )"G&
9、说明:in 的使用方法 q]-CTx$
select * from table1 where a [not] in ('值1','值2','值4','值6') j#C1+Us
10、说明:两张关联表,删除主表中已经在副表中没有的信息 b&y"[1`
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) DRBRs-D
11、说明:四表联查问题: +0,{gDd+
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 ..... [BH^SvE
12、说明:日程安排提前五分钟提醒 P~>E
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ,<^7~d{{3m
13、说明:一条sql 语句搞定数据库分页 ;Jn"^zT
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 6(Qr!<
14、说明:前10条记录 H9x,C/r,
select top 10 * form table1 where 范围 $/*6tsR
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) Xm|Uz`A;
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) O:=%{/6&D
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 SG&VZY
(select a from tableA ) except (select a from tableB) except (select a from tableC) {M7`z,,[
17、说明:随机取出10条数据 8$|<`:~J
select top 10 * from tablename order by newid() e~#"#?
18、说明:随机选择记录 %~V+wqu
select newid() X`[P11`
19、说明:删除重复记录
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) $a.!X8sHB.
20、说明:列出数据库里所有的表名 PY4RwN
select name from sysobjects where type='U' fQ\nK H~
21、说明:列出表里的所有的 r((2.,\Z
select name from syscolumns where id=object_id('TableName') LDj'L~H
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 !besMZ
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type `]Uu` b
显示结果: P9Gjsu #
type vender pcs
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电脑 A 1 ArFsr
电脑 A 1 F-\Swbx+
光盘 B 2 kWF/SsE
光盘 A 2 &=1Ag}l57
手机 B 3 h,Y!d]2w
手机 C 3 A`=;yD
23、说明:初始化表table1 K3jPTAw=#
TRUNCATE TABLE table1 Q}KNtNCpx
24、说明:选择从10到15的记录 W+A-<Rh\
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc jWn!96NhlL
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三、技巧 -BY'E$]4
1、1=1,1=2的使用,在SQL语句组合时用的较多 ^i"C%8
"where 1=1" 是表示选择全部 "where 1=2"全部不选, U~~Y'R\NU
如: `EV"
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if @strWhere !='' ]=s!cfu
begin O*hd@2hd
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere U({20
end -S7PnR6
else W\(u1>lj
begin .Z,3:3,]
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' u!k]Q#2ZR
end 2?",2x09
我们可以直接写成 b-/zt Z@u
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ]r#YU0
2、收缩数据库 K!X>k
--重建索引 r52X}Y
DBCC REINDEX J{GtH[
DBCC INDEXDEFRAG L{v^:
--收缩数据和日志 x.V6C0|6"
DBCC SHRINKDB 8q)wT0A~
DBCC SHRINKFILE TY|5O!
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3、压缩数据库 fI{ZElPp
dbcc shrinkdatabase(dbname) u9WQ0.
4、转移数据库给新用户以已存在用户权限 pNOVyyo>BW
exec sp_change_users_login 'update_one','newname','oldname' 2<dl23
go kI|Vv90l
5、检查备份集 FiTP-~
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' <O`yM2/pS
6、修复数据库 s\c*ibxM,
ALTER DATABASE [dvbbs] SET SINGLE_USER <
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GO
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ya81z4?
GO 9Fe(],AzF
ALTER DATABASE [dvbbs] SET MULTI_USER ryz
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GO #z|\AmZ\
7、日志清除 G;:D6\
SET NOCOUNT ON ^y@RfM=A
DECLARE @LogicalFileName sysname, ~<M/<%o2*
@MaxMinutes INT, sGNVZx
@NewSize INT dg%Orvuz
USE tablename -- 要操作的数据库名 us&!%`
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 _9Pxtf
@MaxMinutes = 10, -- Limit on time allowed to wrap log. wi#]*\N\9
@NewSize = 1 -- 你想设定的日志文件的大小(M) -*[?E!F
-- Setup / initialize =AFTB<7-^
DECLARE @OriginalSize int @w1@|"6vF
SELECT @OriginalSize = size P]bq9!{1
FROM sysfiles RB5fn+FiZ
WHERE name = @LogicalFileName H'Mc]zw_,
SELECT 'Original Size of ' + db_name() + ' LOG is ' + _":yUa0D
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ^!]Hm&.a
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' +ahr-v^R<
FROM sysfiles MC.,n$O}6
WHERE name = @LogicalFileName $}d| ~q\
CREATE TABLE DummyTrans !6eXJ#~[E
(DummyColumn char (8000) not null) Luxo,Ve
DECLARE @Counter INT, 1vcI`8%S+u
@StartTime DATETIME, KtWG2
@TruncLog VARCHAR(255) ]w _,0q
SELECT @StartTime = GETDATE(), 1Aq*|JSk(
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' )7mX]@
DBCC SHRINKFILE (@LogicalFileName, @NewSize) y(pHt
EXEC (@TruncLog) r7tN(2;5
-- Wrap the log if necessary. SrV+Ox
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ;H#'9p ,2
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 1vTncU!
AND (@OriginalSize * 8 /1024) > @NewSize WZk\mSNV
BEGIN -- Outer loop. `{g8A P3
SELECT @Counter = 0 ^}XKhn.S'
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) AL.zF\?
BEGIN -- update /o=V
(
INSERT DummyTrans VALUES ('Fill Log') myT z
DELETE DummyTrans NIeKS_ +
SELECT @Counter = @Counter + 1 !HA[:-JCz
END |>(@n{
EXEC (@TruncLog) I*e85wef
END G Q&9b_
SELECT 'Final Size of ' + db_name() + ' LOG is ' + r`]&{0}23
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + K
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 0G/VbS
FROM sysfiles Jtj_Rl
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WHERE name = @LogicalFileName W_EM
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DROP TABLE DummyTrans nZ>bOP+,
SET NOCOUNT OFF GyV3 ]Qqj
8、说明:更改某个表 fP`g#t)4Tu
exec sp_changeobjectowner 'tablename','dbo' 7@g8nv(p
9、存储更改全部表 ^/K\a
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch i/rdPbq
@OldOwner as NVARCHAR(128), QDlEby m
@NewOwner as NVARCHAR(128) e{edI{g
AS W1X\!Y
DECLARE @Name as NVARCHAR(128) W G2 E3y
DECLARE @Owner as NVARCHAR(128) xq:.|{HUk
DECLARE @OwnerName as NVARCHAR(128) ScrE tN
DECLARE curObject CURSOR FOR *|MHQp'A
select 'Name' = name, DSY:aD!
'Owner' = user_name(uid) [h 8j0Q@Q
from sysobjects N=K|Nw
where user_name(uid)=@OldOwner v*%#Fp,g8
order by name LTu
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OPEN curObject 03*` T
FETCH NEXT FROM curObject INTO @Name, @Owner aG7QLCL
WHILE(@@FETCH_STATUS=0) qu[ ~#
BEGIN Gx?p,Fj
if @Owner=@OldOwner C Ih@H6|
begin D%v4B`4ua'
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ~LPxVYhK
exec sp_changeobjectowner @OwnerName, @NewOwner *loPwV8
end "}UJ~ j).
-- select @name,@NewOwner,@OldOwner #Ag-?k
FETCH NEXT FROM curObject INTO @Name, @Owner bkkhx,Oi[G
END PF@+~FI
close curObject vS-k0g;
deallocate curObject ._m+@Uy]H}
GO O=}4?Xv
10、SQL SERVER中直接循环写入数据 '~i}2e.
declare @i int wZVY h
set @i=1 P0J3ci}^
while @i<30 <va3L y)c&
begin I0 a,mO;m
insert into test (userid) values(@i) ((A]FOIbO
set @i=@i+1 8YC\Bw
end uR{HCZ-
小记存储过程中经常用到的本周,本月,本年函数 u2
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Dateadd(wk,datediff(wk,0,getdate()),-1) FR9<$
Dateadd(wk,datediff(wk,0,getdate()),6) X l#P@60
Dateadd(mm,datediff(mm,0,getdate()),0) @-bX[}.
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ZSq7>}
Dateadd(yy,datediff(yy,0,getdate()),0) FblwQ-D
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) /_E8'qlx
上面的SQL代码只是一个时间段 LZm6\x
Dateadd(wk,datediff(wk,0,getdate()),-1) ~vnG^y>%
Dateadd(wk,datediff(wk,0,getdate()),6) h)BRSs?v_D
就是表示本周时间段. m"\jEfjO
下面的SQL的条件部分,就是查询时间段在本周范围内的: z]ZhvH7-
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) kM5N#|!
而在存储过程中 U'zW; Lt
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) hK"hMyH^
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Ei2Y)_