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。 Y[gj2vNe4g
f>JuxX\G
wTFM:N
一、基础 'kc_OvVA
1、说明:创建数据库 yhe$A<Rl=
CREATE DATABASE database-name b .k
J&c
2、说明:删除数据库 rE"`q1b#
drop database dbname ZVpMR0!
3、说明:备份sql server [ADr
_
--- 创建 备份数据的 device 9`\hG%F
USE master )2}{fFa%
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 2
[a#wz'
--- 开始 备份 TH2D ;uv
BACKUP DATABASE pubs TO testBack .+7GecYz
4、说明:创建新表 :g3n
[7wR
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ]Ff"o7gT
根据已有的表创建新表: (LPMEQhI:
A:create table tab_new like tab_old (使用旧表创建新表) P}o:WI4.cB
B:create table tab_new as select col1,col2... from tab_old definition only GZ\;M6{oh
5、说明:删除新表 58*s\*V`\
drop table tabname Qi|jL*mj&
6、说明:增加一个列 buGW+TrWY
Alter table tabname add column col type 3%m2$\
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。 w[z^B&
7、说明:添加主键: Alter table tabname add primary key(col) !v|j C
说明:删除主键: Alter table tabname drop primary key(col) /-<S F T`
8、说明:创建索引:create [unique] index idxname on tabname(col....) zpr`
删除索引:drop index idxname <Mo_GTOC!
注:索引是不可更改的,想更改必须删除重新建。 d$s1l
9、说明:创建视图:create view viewname as select statement ~oI7TP
删除视图:drop view viewname Vb06z3"r
10、说明:几个简单的基本的sql语句 T#^
选择:select * from table1 where 范围 >#B%gxff
插入:insert into table1(field1,field2) values(value1,value2) gd[jYej'RP
删除:delete from table1 where 范围 KotJ,s]B
更新:update table1 set field1=value1 where 范围 C>Qgd9
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ^.,pq?_
排序:select * from table1 order by field1,field2 [desc] ilQR@yp*
总数:select count as totalcount from table1 ,#&lNQ'I
求和:select sum(field1) as sumvalue from table1 \`o+Le+%
平均:select avg(field1) as avgvalue from table1 &|u
最大:select max(field1) as maxvalue from table1 7]YLe+Ds
最小:select min(field1) as minvalue from table1 <3z]d?u
AJSe +1
Lm\N`
PJN TIa
11、说明:几个高级查询运算词 au2ieZZ[
;A~S){
oju7<b9Ez
A: UNION 运算符 ?b 2
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。 F ^Rt
6Io
B: EXCEPT 运算符 >/1N#S#9
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。 %\=5,9A\
C: INTERSECT 运算符 8Cz_LyL
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。 QRXsLdf$$
注:使用运算词的几个查询结果行必须是一致的。 HDYr?t~V
12、说明:使用外连接 CfQOG7e@
A、left outer join: ./mh9ax
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。 bT}P":*y
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 CQ2{5
B:right outer join: EtJyI&7VK
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。 *7.!"rb8A
C:full outer join: Gvv~P3Dm
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。 3N(s)N_P M
VYkOJAEBg
-_.)~)P
二、提升 *PE1)bF
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) X>EwJ"q#
法一:select * into b from a where 1<>1 Jt"0|+g|
法二:select top 0 * into b from a XodA(73`i
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) M~w
=ZJ@
insert into b(a, b, c) select d,e,f from b; v0 |A
N
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) fM?HZKo
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 0/S|P1!b
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. BFt?%E/]
4、说明:子查询(表名1:a 表名2:b) B#AAG*Ai8
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) jNB|98NN
5、说明:显示文章、提交人和最后回复时间 db^S@}
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b DCM,|FE
6、说明:外连接查询(表名1:a 表名2:b) @Z~lM5n$8
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c BKfcK>%g
7、说明:在线视图查询(表名1:a ) |E0>-\6
select * from (SELECT a,b,c FROM a) T where t.a > 1; gxpR#/(E~
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 jZS6f*$
select * from table1 where time between time1 and time2 Z; Xg5
select a,b,c, from table1 where a not between 数值1 and 数值2
)YRVy
9、说明:in 的使用方法 x;S v&
select * from table1 where a [not] in ('值1','值2','值4','值6') b gGd
10、说明:两张关联表,删除主表中已经在副表中没有的信息 CE-ySIa
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) br+{23&1R#
11、说明:四表联查问题: 'YQ"Lf
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 ..... {NXc<0a(
12、说明:日程安排提前五分钟提醒 6ND,4'6
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Zalgg/.
13、说明:一条sql 语句搞定数据库分页 Kvv&# eO\
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 LGKkT?fcSC
14、说明:前10条记录 FOgF'!K
select top 10 * form table1 where 范围 }UZ$<81=
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.) jFpXTy[>
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) -X5rGp++
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 dG}fpQ3&
(select a from tableA ) except (select a from tableB) except (select a from tableC) X{\>TOk
17、说明:随机取出10条数据 +[8s9{1{C
select top 10 * from tablename order by newid() mb~w .~%
18、说明:随机选择记录 048BQ
select newid() #sdW3m_%
19、说明:删除重复记录 FiJJe
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) :.f =>s]
20、说明:列出数据库里所有的表名 pa Uh+"y>
select name from sysobjects where type='U' F.ryeOJ
21、说明:列出表里的所有的 B;Ab`UX#t
select name from syscolumns where id=object_id('TableName') 5WgdgDb@L
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。 DtG><g}[]
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 |1X^@
显示结果: ~Y@(
type vender pcs e4u$+
电脑 A 1 qCOv4b`
电脑 A 1 >/nS<y>
光盘 B 2 mza1Q~<
光盘 A 2 r<c yxR~
手机 B 3 Lw\ANku
手机 C 3 "12.Bi.O"[
23、说明:初始化表table1 @4Z>;
TRUNCATE TABLE table1 $Ll]h</Z
24、说明:选择从10到15的记录 e5maZ(.;F
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc n
c:^)G
&N GYV
sh[Yu
\Xc6K!HJM
三、技巧 {EGiGwpf
1、1=1,1=2的使用,在SQL语句组合时用的较多 % ribxgmd
"where 1=1" 是表示选择全部 "where 1=2"全部不选, EMzJJe{Cv
如: p8hF`D~
if @strWhere !='' %YG ~ql
begin GJai!$v
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere PF*<_p" j
end Q]Q i
else >|WNsjkU%
begin _JOrGVmD
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' &F9BaJ
end u*Z>&]W_
我们可以直接写成 7'Y 3T[
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere R8P7JY[h
2、收缩数据库 &G7JGar
--重建索引 ?Z
{4iF
DBCC REINDEX B-ReBtN
DBCC INDEXDEFRAG )+RTA
y [k
--收缩数据和日志 1O*5>dkX;%
DBCC SHRINKDB YpoO:
DBCC SHRINKFILE EWNh:<F?
3、压缩数据库 zm)
]cq
dbcc shrinkdatabase(dbname) db$Th=s[
4、转移数据库给新用户以已存在用户权限 zvYkWaa_Qz
exec sp_change_users_login 'update_one','newname','oldname' )dgXS//Y
go F2]v]]F!
5、检查备份集 y[Zl ,v7
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' S-WD?BFC
6、修复数据库 =i }
ALTER DATABASE [dvbbs] SET SINGLE_USER ~Wjm"|c
GO 7tMV*{+Z
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK u$$@Hw
GO 5:/
zbt\C
ALTER DATABASE [dvbbs] SET MULTI_USER I!&|L0Qq
GO )9MmL-7K
7、日志清除 T^g2N`w2
SET NOCOUNT ON I-oI,c%+
DECLARE @LogicalFileName sysname, >(S4h}^I
@MaxMinutes INT, <#<4A0:
@NewSize INT Iq0_X7:{QI
USE tablename -- 要操作的数据库名 T`7;Rl'Q
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 /~NsHStn
@MaxMinutes = 10, -- Limit on time allowed to wrap log. i`)bn1Xm
@NewSize = 1 -- 你想设定的日志文件的大小(M) 35B G&;C
-- Setup / initialize @G[P|^B
DECLARE @OriginalSize int 0b+OB pqN
SELECT @OriginalSize = size ~[dU%I>L^
FROM sysfiles cP%mkh_ri
WHERE name = @LogicalFileName Kj,C9
SELECT 'Original Size of ' + db_name() + ' LOG is ' + h!ZEZ|{
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + EGL1[7It`
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ojU:RRr4l$
FROM sysfiles ~Z!!wDHS
WHERE name = @LogicalFileName }UJS*mR
CREATE TABLE DummyTrans (m80isl
(DummyColumn char (8000) not null) |>@Gbgw^M
DECLARE @Counter INT, CwZ+Pn0
@StartTime DATETIME, 2%U)y;$m2
@TruncLog VARCHAR(255)
(M5w:qbR
SELECT @StartTime = GETDATE(), ,IoPK!5xy
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' T{3C3EE?]
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 5A /8G}'XZ
EXEC (@TruncLog) EKoAIC*?p
-- Wrap the log if necessary. ac"Pn?
q
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired VXXo\LQUU
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) l|z
'Lwwm5
AND (@OriginalSize * 8 /1024) > @NewSize ?9xaBWf
BEGIN -- Outer loop. ?F]Yebp^
SELECT @Counter = 0 Xd/gvg{??0
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 90L,.
BEGIN -- update (G $nN*rlu
INSERT DummyTrans VALUES ('Fill Log') aKXaor@0f.
DELETE DummyTrans Nq6~6Rr
SELECT @Counter = @Counter + 1 A]"$O&l
END opxVxjTT#
EXEC (@TruncLog) S%gb1's
END 5_Yl!=
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 2*Hw6@Jj
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Dw{rjK\TT'
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' xO)vn\uJ
FROM sysfiles c;c'E&9P]
WHERE name = @LogicalFileName R+k-mbvnt
DROP TABLE DummyTrans vKN"o* q
SET NOCOUNT OFF H6(kxpOI\
8、说明:更改某个表 oVutHt
exec sp_changeobjectowner 'tablename','dbo' gXN#<g,:^
9、存储更改全部表 ]Aap4+s
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch E;$)Oz
@OldOwner as NVARCHAR(128), >y)(M(o
@NewOwner as NVARCHAR(128) Ug02G
AS e\x=4i
DECLARE @Name as NVARCHAR(128) <6^MVaD
DECLARE @Owner as NVARCHAR(128) {WUW.(^]G
DECLARE @OwnerName as NVARCHAR(128) y>wrm:b-O
DECLARE curObject CURSOR FOR B5h-JON]-
select 'Name' = name, ^(y=DJ7
'Owner' = user_name(uid) wJ@8-H 8}
from sysobjects q(<#7spz
where user_name(uid)=@OldOwner <ABN/nH
order by name RB<LZHZI
OPEN curObject | n5F_RL
FETCH NEXT FROM curObject INTO @Name, @Owner )w];eF0c
WHILE(@@FETCH_STATUS=0) ''Fy]CwH(
BEGIN UH/) 4Wg
if @Owner=@OldOwner #R$d6N[H
begin |d^r"wbs3
set @OwnerName = @OldOwner + '.' + rtrim(@Name) +;~JHx.~X
exec sp_changeobjectowner @OwnerName, @NewOwner y;Xb."e~
end sPY*2B
-- select @name,@NewOwner,@OldOwner ofbNg_K>
FETCH NEXT FROM curObject INTO @Name, @Owner @/h_v#W
END %}jwuNGA
close curObject 9k8ftxB^
deallocate curObject -BUxQ8/,
GO %^s;{aN*!
10、SQL SERVER中直接循环写入数据 hNBv|&D#
declare @i int 4GWt.+{J$
set @i=1 jqxeON
while @i<30 nM:e<`r
begin p'UY Ht
insert into test (userid) values(@i) ]:`q/iS&
set @i=@i+1 :q=u+h_
end 02E-|p;
小记存储过程中经常用到的本周,本月,本年函数 "&?F6Pi
Dateadd(wk,datediff(wk,0,getdate()),-1) 3Tze`Q 9
Dateadd(wk,datediff(wk,0,getdate()),6) y~'F9E!i
Dateadd(mm,datediff(mm,0,getdate()),0) ppr95Y]^
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 2KVMQH`B9
Dateadd(yy,datediff(yy,0,getdate()),0) hR,VE'A
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Q4e*Z9YJ
上面的SQL代码只是一个时间段 H&jK|]UXoO
Dateadd(wk,datediff(wk,0,getdate()),-1) Sx)b~ *
Dateadd(wk,datediff(wk,0,getdate()),6) `:cnu;
就是表示本周时间段. DpjiE/*
下面的SQL的条件部分,就是查询时间段在本周范围内的: }[ LME Z
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) tWR>I$O8F
而在存储过程中 >Ia{ZbQV
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) H~%HTl
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) &ywAzGV{s