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。 irKM?#h
D`2w>{Y
RZqou|ki
一、基础 H[U"eS."
1、说明:创建数据库 NWII?X#T}
CREATE DATABASE database-name F4=V*/7
2、说明:删除数据库 >|g(/@IO
drop database dbname ?dAy_|
zD
3、说明:备份sql server EEj.Kch}4
--- 创建 备份数据的 device sc$I,|d2
USE master @ x5LrQ_`r
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' O#x=iZI
--- 开始 备份 OzUo}QN
BACKUP DATABASE pubs TO testBack ;><m[ l6
4、说明:创建新表 ^D A<=C-[!
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 5b;~&N4~
根据已有的表创建新表: |a>,FZv8e
A:create table tab_new like tab_old (使用旧表创建新表) ;]^% 6B n
B:create table tab_new as select col1,col2... from tab_old definition only dnCurWjdk
5、说明:删除新表 .g!K| c
drop table tabname ZFRKzPc
{V
6、说明:增加一个列 80 ckh
Alter table tabname add column col type cSYMnB
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 A/ 88WC$v
7、说明:添加主键: Alter table tabname add primary key(col) g,s^qW0vds
说明:删除主键: Alter table tabname drop primary key(col) <j:@ iP
8、说明:创建索引:create [unique] index idxname on tabname(col....) Z^_gS&nDa~
删除索引:drop index idxname YZ^mH <
注:索引是不可更改的,想更改必须删除重新建。 40HhMTZ0-
9、说明:创建视图:create view viewname as select statement #;/ob-
删除视图:drop view viewname ,#K{+1z:
10、说明:几个简单的基本的sql语句 YpEH(tq
选择:select * from table1 where 范围 ##a.=gl
插入:insert into table1(field1,field2) values(value1,value2) 1;eWnb(
删除:delete from table1 where 范围 J(w 3A)(
更新:update table1 set field1=value1 where 范围 :r9<wbr)k0
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! U[W &D%'
排序:select * from table1 order by field1,field2 [desc] dK>sHUu
总数:select count as totalcount from table1 v:]z-zU
求和:select sum(field1) as sumvalue from table1 S9dXkd
平均:select avg(field1) as avgvalue from table1 KRb'kW
最大:select max(field1) as maxvalue from table1 1\-r5e; BE
最小:select min(field1) as minvalue from table1 N."x@mV
d8K|uEHVz
.:~E.b
z"f+;1
11、说明:几个高级查询运算词 vF1Fcp.@
w$"^)EG,7
nB6 $*'
A: UNION 运算符 O2"5\@HfE
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。 4|;Ys-Q
B: EXCEPT 运算符 $+$4W\-=X
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 USZBk0$
C: INTERSECT 运算符 YFP<^y=
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。 }!V-FAL
注:使用运算词的几个查询结果行必须是一致的。 UHR%0ae
12、说明:使用外连接 Lr0:yo
A、left outer join: k5)a|
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。 _fS4a134R
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])e}&i
B:right outer join: Sm;@MI<@/
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。 2WC$r8E
C:full outer join: *U +<Hv`C
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 jc HyRR1R
lcK4 Uq\q
0[E\h
二、提升 n0g8B
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 7MQh,J!"
法一:select * into b from a where 1<>1 &z@}9U*6b
法二:select top 0 * into b from a iw%""q(`
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 3:T~$M`]
insert into b(a, b, c) select d,e,f from b; 934@Z(aUH
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) Hb0_QT~
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 aNP\Q23D
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. d|>/eb.R
4、说明:子查询(表名1:a 表名2:b) `R!Q(rePx
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) g{CU1c)B
5、说明:显示文章、提交人和最后回复时间 k/1S7X[
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b hDXaCift
6、说明:外连接查询(表名1:a 表名2:b) [9G=x[
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c "RgP!
7、说明:在线视图查询(表名1:a ) AkCy
C1
select * from (SELECT a,b,c FROM a) T where t.a > 1; a(X V~o
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+j
!CvtI
select * from table1 where time between time1 and time2 ,0{x-S0jX<
select a,b,c, from table1 where a not between 数值1 and 数值2 xxA^A
9、说明:in 的使用方法 HvmE'O8
select * from table1 where a [not] in ('值1','值2','值4','值6') A?ho<@^
10、说明:两张关联表,删除主表中已经在副表中没有的信息 u~PZK.Uf0
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) KW$.Yy
11、说明:四表联查问题: _|T{2LvwT
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... \i+Ad@)
12、说明:日程安排提前五分钟提醒 *Qyu
QF
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 M4(57b[`
13、说明:一条sql 语句搞定数据库分页 (I/iD.A
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 ]-_ ma
14、说明:前10条记录 "z*.Bk
select top 10 * form table1 where 范围 ?TJ4L/"(k6
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) sDAP'&
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) E1SWZ&';
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 bo1J'pU
(select a from tableA ) except (select a from tableB) except (select a from tableC) sf/m@425
17、说明:随机取出10条数据 TbLU[(m-n
select top 10 * from tablename order by newid() ~'F.tB
18、说明:随机选择记录 H3 -?cy
select newid() e=3C*+lq\
19、说明:删除重复记录 ?d+ri
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) [5tvdW6Z&
20、说明:列出数据库里所有的表名 A1r%cs
select name from sysobjects where type='U' %J Jp/I
21、说明:列出表里的所有的 `vz7}TY
select name from syscolumns where id=object_id('TableName') g)=$zXWhP
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。 :zY;eJK m
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 f@[)*([
显示结果: %a
FZbLK
type vender pcs -*Tf.c
电脑 A 1 ',/# |
电脑 A 1 W =;,ls
光盘 B 2 O(VWJ@EHn
光盘 A 2 rT\~VJ>+i
手机 B 3 mE_%
手机 C 3 4>OS2b`.;
23、说明:初始化表table1 I L,l XB<
TRUNCATE TABLE table1 v|KIVBkbT
24、说明:选择从10到15的记录 +r7hc;+G
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ]=9 d'WL
{]dG 9
\GQRpJ#h1
WP?]"H
三、技巧
"a9j2+9
1、1=1,1=2的使用,在SQL语句组合时用的较多 2vU-9p {
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Pm%5c\ef
如: P(DEf(
if @strWhere !='' -%|
]
d ;
begin ;Yv{)@'Bc
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere P j,H]
end 8:)[.
else ?zQW9e
begin &iZt(XD
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' K\xnQeS<W
end QT
zN
我们可以直接写成 -2!S>P Zs
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere }V*?~.R
2、收缩数据库 `Tf}h8*
--重建索引 ` &bF@$((
DBCC REINDEX kvuRT`/
DBCC INDEXDEFRAG 6212*Z_Af
--收缩数据和日志 'n>44_7 L
DBCC SHRINKDB %hN(79:g
DBCC SHRINKFILE ,i|K} Y&
3、压缩数据库 ^/$dSXKF
dbcc shrinkdatabase(dbname) Y652&{>q
4、转移数据库给新用户以已存在用户权限 ITg:OOQ
exec sp_change_users_login 'update_one','newname','oldname' ,A $IFE
go (F 9P1Iq
5、检查备份集 rsa_)iBC
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' U;IGV~oT
6、修复数据库 $MGKGWx@E
ALTER DATABASE [dvbbs] SET SINGLE_USER ,X1M!'
GO (X-(
WMsqQ
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ]f?r@U'AS|
GO 7)[2Ud8
ALTER DATABASE [dvbbs] SET MULTI_USER +H?g9v40
GO VcXr!4M
7、日志清除 ""
>Yw/'
SET NOCOUNT ON ,A7:zxnc.V
DECLARE @LogicalFileName sysname, Pz[UAJ
@MaxMinutes INT, mdyl;e{0
@NewSize INT n1GX`K
USE tablename -- 要操作的数据库名 Dt> tTU 6
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 65JG#^)KaX
@MaxMinutes = 10, -- Limit on time allowed to wrap log. *0Z6H-Do,
@NewSize = 1 -- 你想设定的日志文件的大小(M) 3 !8#wn
-- Setup / initialize (9ZW^flY
DECLARE @OriginalSize int G_5{5Ar
SELECT @OriginalSize = size Y0kcxpK/
FROM sysfiles }!k?.(hpE
WHERE name = @LogicalFileName 9H;Os:"\|
SELECT 'Original Size of ' + db_name() + ' LOG is ' + }yn%_KQ0
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + gK;dfrU.8Y
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' qoH:_o8ClO
FROM sysfiles {5D%<Te
WHERE name = @LogicalFileName aMGh$\Pg
CREATE TABLE DummyTrans fa,:d8
(DummyColumn char (8000) not null) ,jeHL@>w[
DECLARE @Counter INT, SP<Sv8Okj
@StartTime DATETIME, \m}a%/
@TruncLog VARCHAR(255) <}A6 )=T
SELECT @StartTime = GETDATE(), N\&VJc
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 2;*G!rE&*`
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 0tL5t7/Gr
EXEC (@TruncLog) d}fd^x/
-- Wrap the log if necessary. Sz<:WY/(x
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Gey-8
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) _<jU! R
AND (@OriginalSize * 8 /1024) > @NewSize ,mvFeo;@f
BEGIN -- Outer loop. H)E,([
SELECT @Counter = 0 g.Qn,l]X/p
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 6Iv};f"Y
BEGIN -- update h lc!}{$%8
INSERT DummyTrans VALUES ('Fill Log') c^'bf_~-W
DELETE DummyTrans "~EAt$
SELECT @Counter = @Counter + 1 9S17Lr*c
END x9\{a
EXEC (@TruncLog) Z:,\FB_U
END \Gk}Fer
SELECT 'Final Size of ' + db_name() + ' LOG is ' + eN|zD?ba&
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + T"3LO[j+
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ujE~#b}X
FROM sysfiles Fje
/;p
WHERE name = @LogicalFileName *oIIcE4g7
DROP TABLE DummyTrans m(:R (K(je
SET NOCOUNT OFF 9[*P`*&
8、说明:更改某个表 i( +Uv tgs
exec sp_changeobjectowner 'tablename','dbo' +}(]7du
9、存储更改全部表 }id)~h_@
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch R\n@q_!`X
@OldOwner as NVARCHAR(128), W7~_XI
@NewOwner as NVARCHAR(128) u81F^72U
AS ?P9VdS1-
DECLARE @Name as NVARCHAR(128) )v+&l9D
DECLARE @Owner as NVARCHAR(128) pX3E l$p
DECLARE @OwnerName as NVARCHAR(128) UHi^7jQ
DECLARE curObject CURSOR FOR hUp3$4w
select 'Name' = name, f>mEX='w
'Owner' = user_name(uid) y6sY?uu
from sysobjects bOrE86v:
where user_name(uid)=@OldOwner cdH`#X
order by name xDekC~Zq
OPEN curObject SI%J+Y7
FETCH NEXT FROM curObject INTO @Name, @Owner =? q&/
cru
WHILE(@@FETCH_STATUS=0) Gv 8Z
BEGIN HlkjyD8
if @Owner=@OldOwner <b\.d^=B
begin X3gYe-2
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 23p.g5hJi
exec sp_changeobjectowner @OwnerName, @NewOwner =8p[ (<F=
end i
^N}avO
-- select @name,@NewOwner,@OldOwner s%>u[-9U
FETCH NEXT FROM curObject INTO @Name, @Owner n
Zx^ej\
END Sqmjf@o$>
close curObject Y%]g,mG
deallocate curObject 6~s{HI!
GO c(?O E'
"Z
10、SQL SERVER中直接循环写入数据 MfLus40;n
declare @i int l{ fL~O
set @i=1 SFsT^f<
while @i<30 sZqi)lo-s
begin G~*R6x2g
insert into test (userid) values(@i) YWi Y[
set @i=@i+1 [czWUD
end :t+LuH g
小记存储过程中经常用到的本周,本月,本年函数 5HvYy
*B/
Dateadd(wk,datediff(wk,0,getdate()),-1) Xe/7rhov
Dateadd(wk,datediff(wk,0,getdate()),6) 95D(0qv
Dateadd(mm,datediff(mm,0,getdate()),0) x5U;i
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ,(c'h:@M
Dateadd(yy,datediff(yy,0,getdate()),0) ND 8;1+3
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) b_~KtMO
上面的SQL代码只是一个时间段 'e
x/IqbK
Dateadd(wk,datediff(wk,0,getdate()),-1) T[0CD'|E
Dateadd(wk,datediff(wk,0,getdate()),6) "6?Y$y/wm
就是表示本周时间段. =<=[E:B
下面的SQL的条件部分,就是查询时间段在本周范围内的: )In;nc
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) .J5or
而在存储过程中 NH1|_2
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) n=!5ha%#N
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) )s 1
Ei9J