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。 Dj0D.}`~
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一、基础 T7Ju7_q}
1、说明:创建数据库 ~eiD(04^r*
CREATE DATABASE database-name "b)EH/s
2、说明:删除数据库 Kz]\o"K
drop database dbname 1@~ 1vsJ
3、说明:备份sql server qR%as0;
--- 创建 备份数据的 device YWk+}y}^d
USE master LW!4KA]
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' yhnPS4DC
--- 开始 备份 {t]8#[lo
BACKUP DATABASE pubs TO testBack &$~irI
4、说明:创建新表 6"r _Y7%
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) :/>Zky8,k
根据已有的表创建新表: _ vAc/_N
A:create table tab_new like tab_old (使用旧表创建新表) F"'
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B:create table tab_new as select col1,col2... from tab_old definition only T w1&<S
5、说明:删除新表 wRX#^;O9?>
drop table tabname [l~G7u.d
6、说明:增加一个列 DTd qwe6pi
Alter table tabname add column col type ? Z2`f6;W4
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。 j5~~%
7、说明:添加主键: Alter table tabname add primary key(col) 8\?H`NN
说明:删除主键: Alter table tabname drop primary key(col) "837b/>/
8、说明:创建索引:create [unique] index idxname on tabname(col....) = ^%*: iT
删除索引:drop index idxname ? a/\5`gnN
注:索引是不可更改的,想更改必须删除重新建。 [BEQ ~A_I
9、说明:创建视图:create view viewname as select statement q1rD>n&d
删除视图:drop view viewname eK\i={va
10、说明:几个简单的基本的sql语句 uj)fah?Wg
选择:select * from table1 where 范围 x-q_sZ^8
插入:insert into table1(field1,field2) values(value1,value2) +7y#c20
删除:delete from table1 where 范围 YlZ&4
更新:update table1 set field1=value1 where 范围 @qF:v]=_@
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ,"?8
排序:select * from table1 order by field1,field2 [desc] &}#zG5eu
总数:select count as totalcount from table1 ]KUeSg|
求和:select sum(field1) as sumvalue from table1 9!dG Xq
平均:select avg(field1) as avgvalue from table1 +z~bH!$2
最大:select max(field1) as maxvalue from table1 < 7*9b
最小:select min(field1) as minvalue from table1 ;2gO(
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11、说明:几个高级查询运算词 -x!JTx[K
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A: UNION 运算符 r\ C"Fx^
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。 eyn-bw
B: EXCEPT 运算符 u!FF{~5cs
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。 60xL.Z
C: INTERSECT 运算符 !2.eJ)G
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%{d
注:使用运算词的几个查询结果行必须是一致的。 DX/oHkLD'
12、说明:使用外连接 AO(zl*4
A、left outer join: b4(,ls
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。 fBBtS S
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 mPo.Z"uy7
B:right outer join: gz Dfx&.0
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。 |[)pQGw
C:full outer join: ?YF2Uc8z%2
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。 6|4ID"
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二、提升 fY|[YPGO^
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) DyUS^iz~o
法一:select * into b from a where 1<>1 Q $Sp'
法二:select top 0 * into b from a p?4,YV|#
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) *y|zF6
insert into b(a, b, c) select d,e,f from b; 1c*;Lr.K
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) u Vo"_c w
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Q&w"!N
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ?kF?
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4、说明:子查询(表名1:a 表名2:b)
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select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 3sl6$NKo
5、说明:显示文章、提交人和最后回复时间 9&Z+K'$=
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b \0FwxsL
6、说明:外连接查询(表名1:a 表名2:b) tF.N
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c mp*?GeV?M
7、说明:在线视图查询(表名1:a ) O;0VKNn['
select * from (SELECT a,b,c FROM a) T where t.a > 1; `4ti?^BNm
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 @qB>qD~WsD
select * from table1 where time between time1 and time2 $s"-r9@q
select a,b,c, from table1 where a not between 数值1 and 数值2 w,OPM}) il
9、说明:in 的使用方法 PlwM3lrj
select * from table1 where a [not] in ('值1','值2','值4','值6') $dsLU5]1o
10、说明:两张关联表,删除主表中已经在副表中没有的信息 /RWD\u<l
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) <00=bZzX
11、说明:四表联查问题: S Erh"~[
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ~G.MaSm
12、说明:日程安排提前五分钟提醒 WwxV}?Cf+
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 @c).&7
13、说明:一条sql 语句搞定数据库分页 UQbk%K2
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 x4v&%d=M
14、说明:前10条记录 lWUQkS
select top 10 * form table1 where 范围 |*l^<= =
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) ~m[Gp;pL
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) XR$i:kL,,
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 =o'g5Be<F
(select a from tableA ) except (select a from tableB) except (select a from tableC) b)r;a5"<5
17、说明:随机取出10条数据 *aGJ$ P0
select top 10 * from tablename order by newid() C(M ?$s`
18、说明:随机选择记录 1E0!?kRK
select newid() 3jHE,5m
19、说明:删除重复记录 7W>(T8K X\
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Qm_;o(
20、说明:列出数据库里所有的表名 }#&L
select name from sysobjects where type='U' g@Rs.Zq
21、说明:列出表里的所有的 7JBr{3;eS
select name from syscolumns where id=object_id('TableName') {e0(M*u
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 z|zEsDh;
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type Q(4~r+
显示结果: HmHM#~5(`
type vender pcs F6"s&3D{
电脑 A 1 I6,||!sZ
电脑 A 1 L XTtV0F
光盘 B 2 B[t>T>~
光盘 A 2 #+$PD`j
手机 B 3 LZQG.
手机 C 3 (i1p6
23、说明:初始化表table1 Nv3u)?A3w
TRUNCATE TABLE table1 [&(~1C|C
24、说明:选择从10到15的记录 ,R=$qi|
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ~g;)8X;;+
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三、技巧 o'8%5M@
1、1=1,1=2的使用,在SQL语句组合时用的较多 }rF4M1+B\
"where 1=1" 是表示选择全部 "where 1=2"全部不选, bH!_0+$P
如: ^oNcZK>
if @strWhere !='' OjrZ6
begin 9_~9?5PU
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere >:BgatyPH
end xc7Rrh]}
else '}-QZ$|*
begin 9Q\RCl_1
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' F)@zo/u5L
end ;Eh"]V,e
我们可以直接写成 5Fbb5`(
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere FtlJ3fB@
2、收缩数据库 *^CN2tm
--重建索引 q Ll4t/p
DBCC REINDEX N2lz{
DBCC INDEXDEFRAG We'= /!
--收缩数据和日志 ?a'EkZ.dB
DBCC SHRINKDB TP)o0U
DBCC SHRINKFILE ?[%.4i;-h
3、压缩数据库 @q{.
dbcc shrinkdatabase(dbname) 'ITZz n*
4、转移数据库给新用户以已存在用户权限 :Y4Sdj
exec sp_change_users_login 'update_one','newname','oldname' F*-'8~T
go >ul&x!?@
5、检查备份集 !(3[z>
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' +>yspOEz
6、修复数据库 0wAB;|~*62
ALTER DATABASE [dvbbs] SET SINGLE_USER vFeR)Ox's
GO GH&5m44
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ;alt% :$n
GO ~RZN+N
ALTER DATABASE [dvbbs] SET MULTI_USER ^==Tv+T9U
GO JOs
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7、日志清除 -lXQQ#V
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SET NOCOUNT ON <vu~EY0.
DECLARE @LogicalFileName sysname, CIRMAX
@MaxMinutes INT, o@C|*TXN
@NewSize INT +U?73cYN
USE tablename -- 要操作的数据库名 n8D'fvY
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 a.ijc>K
@MaxMinutes = 10, -- Limit on time allowed to wrap log. GoPMWbI7
@NewSize = 1 -- 你想设定的日志文件的大小(M) @gQ?cU 7
-- Setup / initialize \x5>H:\Y
DECLARE @OriginalSize int ZT`"
{#L
SELECT @OriginalSize = size fd62m]X
FROM sysfiles "Nz"|-3Irv
WHERE name = @LogicalFileName 1`l(H4
SELECT 'Original Size of ' + db_name() + ' LOG is ' + MYR\W*B'b
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + u=E &jL5U
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Ec }9R3 m
FROM sysfiles #MbY+[Y@v
WHERE name = @LogicalFileName #jO2Zu2`}
CREATE TABLE DummyTrans NGEE'4!i7T
(DummyColumn char (8000) not null) yA7O<p+
DECLARE @Counter INT, \Rha7O
@StartTime DATETIME, llCE}Vdh
@TruncLog VARCHAR(255) (&, E}{p9
SELECT @StartTime = GETDATE(), i.7$~}
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' z`D|O|#q
DBCC SHRINKFILE (@LogicalFileName, @NewSize) >)mF'w
EXEC (@TruncLog) KvI/!hl\
-- Wrap the log if necessary. ^9YS dFH/
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ^PMA"!n8
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 8v)HTD/C
AND (@OriginalSize * 8 /1024) > @NewSize >xH?`I7;f
BEGIN -- Outer loop. y5VohVa`
SELECT @Counter = 0 :R3&R CTZ
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) U@(8)[?nxn
BEGIN -- update t{B6W)q
INSERT DummyTrans VALUES ('Fill Log') {7v|\6@e3
DELETE DummyTrans brLu~]I
SELECT @Counter = @Counter + 1 {n S(B
END i?)bF!J
EXEC (@TruncLog) ?*<1B
END w2^s}NO
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 6.a>7-K}%
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ^{NN-
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' VRHS 4
FROM sysfiles x_l8&RIB*
WHERE name = @LogicalFileName .dvs&+I
DROP TABLE DummyTrans R/6
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SET NOCOUNT OFF >z,Y%A
8、说明:更改某个表 R1.Yx?
exec sp_changeobjectowner 'tablename','dbo' R/2L9Lcv
9、存储更改全部表 HD,6
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch #}8VUbJ
@OldOwner as NVARCHAR(128), OSom-?|w
@NewOwner as NVARCHAR(128) psS^
AS $-E<{
DECLARE @Name as NVARCHAR(128) <Zh\6*3:ab
DECLARE @Owner as NVARCHAR(128) ]*0t?'go'
DECLARE @OwnerName as NVARCHAR(128) !u`f?=s;
DECLARE curObject CURSOR FOR ,3)JZM
select 'Name' = name, r 2{7h>
'Owner' = user_name(uid) ] HRHF'4
from sysobjects DvA#zX[
where user_name(uid)=@OldOwner m5hu;>gt
order by name EAF\7J*
OPEN curObject 2"o<>d
FETCH NEXT FROM curObject INTO @Name, @Owner [u-=<hnoa
WHILE(@@FETCH_STATUS=0) j",*&sy
BEGIN 1o)<23q`)
if @Owner=@OldOwner Ysi@wK-LnF
begin _sHeB7K
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Aiqb*v$
exec sp_changeobjectowner @OwnerName, @NewOwner M2.*]AL
end 6O@Lx]t
-- select @name,@NewOwner,@OldOwner *6v5JH&K
FETCH NEXT FROM curObject INTO @Name, @Owner cc"<H}g>`
END \`8F.oZ^)
close curObject J.0&gP V
deallocate curObject Af^9WJ
GO l8lJ &
10、SQL SERVER中直接循环写入数据 *LvdrPxU=
declare @i int UG6\OgkL+
set @i=1 9s*UJIL
while @i<30 I."s&]FZ
begin BpF}H^V-
insert into test (userid) values(@i) Y2+YmP*z`
set @i=@i+1 -3XnUGK
end Pfm B{
小记存储过程中经常用到的本周,本月,本年函数 %Wc$S]>i
Dateadd(wk,datediff(wk,0,getdate()),-1) #4Cf-$J
Dateadd(wk,datediff(wk,0,getdate()),6) {|e7^_ ke
Dateadd(mm,datediff(mm,0,getdate()),0) E/E|*6R
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) J/[PA[Rf
Dateadd(yy,datediff(yy,0,getdate()),0) BJsN~`=r
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) t4-0mNBZt$
上面的SQL代码只是一个时间段 ^;Yjs.bI`F
Dateadd(wk,datediff(wk,0,getdate()),-1) X0KUnxw
Dateadd(wk,datediff(wk,0,getdate()),6) ;!m_RQPFF
就是表示本周时间段. \,`iu=YZv
下面的SQL的条件部分,就是查询时间段在本周范围内的: /EvT%h?p
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 6p14BruV
而在存储过程中 nYK!'x$
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ==bT0-M.~
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) @_h=,g#@