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。 >u`Ci>tY
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一、基础 ZI!;~q
1、说明:创建数据库 MLmk=&d
CREATE DATABASE database-name Y=UN`vRR
2、说明:删除数据库 h9%.tGx
drop database dbname iqTmgE-
3、说明:备份sql server H M\}C.u
--- 创建 备份数据的 device [}l
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USE master ?zXlLud8
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' .6i +_B|
--- 开始 备份 NCx)zJ\S
BACKUP DATABASE pubs TO testBack ^X*l&R_=R
4、说明:创建新表 p!(]`N
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) K!G/iz9SB
根据已有的表创建新表: Kku@!lv
A:create table tab_new like tab_old (使用旧表创建新表) wD<W'K
B:create table tab_new as select col1,col2... from tab_old definition only f./j%R@
5、说明:删除新表 m?)F@4]
drop table tabname ns[h_g!j;
6、说明:增加一个列 *^%ohCUi
Alter table tabname add column col type %G] W Oq=q
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。 `]2y=f<{X
7、说明:添加主键: Alter table tabname add primary key(col)
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说明:删除主键: Alter table tabname drop primary key(col) ( 2KopL
8、说明:创建索引:create [unique] index idxname on tabname(col....) I \6^]pi,
删除索引:drop index idxname .18MMzdN
注:索引是不可更改的,想更改必须删除重新建。 $I3}%'`+
9、说明:创建视图:create view viewname as select statement }Do$oyAV$G
删除视图:drop view viewname V#-8[G6Ra
10、说明:几个简单的基本的sql语句 4L2TsuLw
选择:select * from table1 where 范围 a&`Lfw"
插入:insert into table1(field1,field2) values(value1,value2) ]u
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删除:delete from table1 where 范围 `[4{]jX+<
更新:update table1 set field1=value1 where 范围 Z@#kivcpz
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! g^2H(}frc
排序:select * from table1 order by field1,field2 [desc]
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总数:select count as totalcount from table1 A@ G%*\UZ
求和:select sum(field1) as sumvalue from table1 OWHHN<
平均:select avg(field1) as avgvalue from table1 UZW)%
最大:select max(field1) as maxvalue from table1 OmECvL'Z
最小:select min(field1) as minvalue from table1 n\4sNoFI
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11、说明:几个高级查询运算词
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A: UNION 运算符 b U>.Bp]
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。 v1s0kdR,>
B: EXCEPT 运算符 Al}%r85
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。 Ykj+D7rA:
C: INTERSECT 运算符 ohB@ij C!
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。 ncij)7c)u
注:使用运算词的几个查询结果行必须是一致的。 *f+DV[DF
12、说明:使用外连接 <a%RKjQvT
A、left outer join: {c AGOx wd
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。 +zsB ~Vz
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 e:WKb9nT
B:right outer join: Ne2eBmY}(
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。 n]WVT@
C:full outer join: X~g~U|B@
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。 ,A!0:+
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二、提升 /.[78:G\,
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) n ]P,5
法一:select * into b from a where 1<>1 b(:U]>J
法二:select top 0 * into b from a WQYw@M~4Q!
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) fnU;DS]W
insert into b(a, b, c) select d,e,f from b; XXPpj< c
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) QpMi+q
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 5*Y(%I<
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. A#Jx6T`a
4、说明:子查询(表名1:a 表名2:b) f5&K=4khn
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) ,9~2#[|lq
5、说明:显示文章、提交人和最后回复时间 t\\`#gc9~i
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b |jTRIMj%,_
6、说明:外连接查询(表名1:a 表名2:b) `KmM*_a
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Z {*<Gx
7、说明:在线视图查询(表名1:a ) ?hnxc0~P
select * from (SELECT a,b,c FROM a) T where t.a > 1; V82N8-l
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 `-82u :"
select * from table1 where time between time1 and time2 _air'XQ&!
select a,b,c, from table1 where a not between 数值1 and 数值2 Meo.
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9、说明:in 的使用方法 /~;om\7r
select * from table1 where a [not] in ('值1','值2','值4','值6') pK@8= +
10、说明:两张关联表,删除主表中已经在副表中没有的信息
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) <Is~DjIav
11、说明:四表联查问题: di]TS9&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 ..... 5X,|Pn
12、说明:日程安排提前五分钟提醒 #w#:f
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 _tQR3I5
13、说明:一条sql 语句搞定数据库分页 ?=0BU}
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 WBY_%RTx
14、说明:前10条记录 JWvL
select top 10 * form table1 where 范围 c^EU&q{4
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.) F>s5<pKAX
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Fhk`qh'i
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 #hF(`oX}4K
(select a from tableA ) except (select a from tableB) except (select a from tableC) oD&axNk
17、说明:随机取出10条数据 jS| 9jg:
select top 10 * from tablename order by newid() 8(""ui8
18、说明:随机选择记录 <e@+w6Kp'7
select newid() QL`Hb p
19、说明:删除重复记录 qjmlwVw
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) xv>]e <":
20、说明:列出数据库里所有的表名 XMw*4j2E
select name from sysobjects where type='U' >K-S&Y
21、说明:列出表里的所有的 QNm8`1
select name from syscolumns where id=object_id('TableName') `ehcj
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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。 i9j#Tu93 f
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 fu $<*Sa2
显示结果: NNP ut$.
type vender pcs /K\]zPq
电脑 A 1 /V$U%0
电脑 A 1 Z2D^]
光盘 B 2 }GL@?kAGR5
光盘 A 2 zX}t1:nc
手机 B 3 h3t);}Y}D9
手机 C 3 rki0! P`
23、说明:初始化表table1 VH7nyqEM
TRUNCATE TABLE table1 ![9umsx
24、说明:选择从10到15的记录 V3<H8pL
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc CWw#0
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三、技巧 db`L0JB
1、1=1,1=2的使用,在SQL语句组合时用的较多 Ws*UhJY<GS
"where 1=1" 是表示选择全部 "where 1=2"全部不选, =a^}]k}
如: :B
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if @strWhere !='' p;n"zr8U
begin Tqj:C8K{
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere D,P{ ,/
end z^^)n
else N|\Q:<!2_w
begin cogIkB&Ju
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ,u_ Z0S M
end :kQydCuK
我们可以直接写成 Bvsxn5z+:
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere _T\cJcWf
2、收缩数据库 m6Mko2
--重建索引 t4v@d
DBCC REINDEX @jY=b<
DBCC INDEXDEFRAG &$g{i:)Z
--收缩数据和日志 ;7E
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DBCC SHRINKDB &OsO _F
DBCC SHRINKFILE <sli!rv
3、压缩数据库 y,s`[=CT
dbcc shrinkdatabase(dbname) h yK&)y?~
4、转移数据库给新用户以已存在用户权限 i8->3uB
exec sp_change_users_login 'update_one','newname','oldname' ,9Si3vn
go E.eUd4XG
5、检查备份集 #gsJ
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' cPy/}A
6、修复数据库 {ep(_1
ALTER DATABASE [dvbbs] SET SINGLE_USER Oe
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GO xtO#reL"q?
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK yc+pNC)ue_
GO !
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ALTER DATABASE [dvbbs] SET MULTI_USER AW8*bq1
GO {;vLM*
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7、日志清除 03H0(ku=
SET NOCOUNT ON <NWq03:&
DECLARE @LogicalFileName sysname, ZXl_cq2r
@MaxMinutes INT, 2"6bz^>}
@NewSize INT ]Bj2; <@y
USE tablename -- 要操作的数据库名 'S%H"W\
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 {hFH6]TA
@MaxMinutes = 10, -- Limit on time allowed to wrap log. |p.|zH
@NewSize = 1 -- 你想设定的日志文件的大小(M) ir|c<~_=
-- Setup / initialize Kk`LuS?
DECLARE @OriginalSize int r4m z
SELECT @OriginalSize = size \zKO5,qw
FROM sysfiles +\]Gu(z<
WHERE name = @LogicalFileName )M><09
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 7YFEyX10d
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + \{v e6`7Rn
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' lFl(Sww!\
FROM sysfiles #/B g5:
WHERE name = @LogicalFileName %
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CREATE TABLE DummyTrans 6=:s3I^
(DummyColumn char (8000) not null) ! k 1 Ge+
DECLARE @Counter INT, @;\0cEn>
@StartTime DATETIME, Q_>W!)p Gz
@TruncLog VARCHAR(255) rCUGaf~
SELECT @StartTime = GETDATE(), nF
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ]f_`w81[
DBCC SHRINKFILE (@LogicalFileName, @NewSize) h0$Y;=YA
EXEC (@TruncLog) 6EeO\Qj{
-- Wrap the log if necessary. eG7Yyz+t$
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 9l(T>B2a
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) )2a)$qx;
AND (@OriginalSize * 8 /1024) > @NewSize ]I_*+^?tI
BEGIN -- Outer loop. S$ffTdRz
SELECT @Counter = 0 :V1j*)
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) tI)|y?q
BEGIN -- update .cm2L,1h
INSERT DummyTrans VALUES ('Fill Log') "VDMO^
DELETE DummyTrans Al=ByX @
SELECT @Counter = @Counter + 1 y @S_CB47
END Y_K W9T_
EXEC (@TruncLog) 1ktxG1"1
END TJ1h[
SELECT 'Final Size of ' + db_name() + ' LOG is ' + PMUW<UI
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Lw2VdFi>E&
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' IVY)pS"pR"
FROM sysfiles \W]gy_=D{
WHERE name = @LogicalFileName SL-;h#-y
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DROP TABLE DummyTrans G[1\5dK*uR
SET NOCOUNT OFF -n8d#Qm)
8、说明:更改某个表 oC-v>&bW
exec sp_changeobjectowner 'tablename','dbo' z0OxJ e
9、存储更改全部表 `nKN|6o#x
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch =r*Ykd;W|E
@OldOwner as NVARCHAR(128), Ek1c >s,t
@NewOwner as NVARCHAR(128) 2,wwI<=E'
AS q
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DECLARE @Name as NVARCHAR(128) ?xrOhA9
DECLARE @Owner as NVARCHAR(128) vxHFNGI
DECLARE @OwnerName as NVARCHAR(128) T;?k]4.X
DECLARE curObject CURSOR FOR $dF3@(p
select 'Name' = name, i[@13kr
'Owner' = user_name(uid) P#7=h:.522
from sysobjects Qn,6s%n
where user_name(uid)=@OldOwner s M*ay,v;
order by name 2 rr=FJ
OPEN curObject pQK SPr
FETCH NEXT FROM curObject INTO @Name, @Owner =MMd&
WHILE(@@FETCH_STATUS=0) l<BV{Gl
BEGIN !1fZ7a
if @Owner=@OldOwner U8AH,?]#
begin QeG9CS)E}j
set @OwnerName = @OldOwner + '.' + rtrim(@Name) vaGF(hfTA
exec sp_changeobjectowner @OwnerName, @NewOwner N@L{9ak1
end -sfv"?
-- select @name,@NewOwner,@OldOwner ;}j(x;l>t
FETCH NEXT FROM curObject INTO @Name, @Owner w7o`BR
END 2 U]d1
close curObject r34MDUZdI
deallocate curObject RFyMRE!?
GO y;uR@{
10、SQL SERVER中直接循环写入数据 z V\+za,
declare @i int t2s/zxt
set @i=1 wV"`Du7E;
while @i<30 "J`&"_CyZ
begin +l/v`=C
insert into test (userid) values(@i) CF2Bd:mfZ
set @i=@i+1 :Ys~Lt54
end VOLj#H
小记存储过程中经常用到的本周,本月,本年函数 l6&\~Z(
Dateadd(wk,datediff(wk,0,getdate()),-1) EgU#r@7I
Dateadd(wk,datediff(wk,0,getdate()),6) =jJEl=*S
Dateadd(mm,datediff(mm,0,getdate()),0) o]Rlivahm
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) qQi\/~Y[:
Dateadd(yy,datediff(yy,0,getdate()),0) hg(<>_~
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) uTxa5j
上面的SQL代码只是一个时间段 m^G(qoZ]
Dateadd(wk,datediff(wk,0,getdate()),-1) P0jr>j@^-
Dateadd(wk,datediff(wk,0,getdate()),6) b.@a,:"
就是表示本周时间段. {VE
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下面的SQL的条件部分,就是查询时间段在本周范围内的: 'Vo8|?.WhX
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) S k~"-HL|
而在存储过程中 n+Kv^Y`qxO
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) -g]Rs!w'
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) %^pi