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。 I:o.%5)
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一、基础 f26hB;n
1、说明:创建数据库 JrwR:_+|
CREATE DATABASE database-name kSU]~x
2、说明:删除数据库 '>dx~v %
drop database dbname fqD1Ej
3、说明:备份sql server JX2@i8[~
--- 创建 备份数据的 device u|M_O5^
USE master oGqbk x
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' YjwC8#$
--- 开始 备份 [UYE.$Y#(
BACKUP DATABASE pubs TO testBack PG'+vl
4、说明:创建新表 kTS#>uS
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..)
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根据已有的表创建新表: +{H0$4y
A:create table tab_new like tab_old (使用旧表创建新表) >vc$3%L[$
B:create table tab_new as select col1,col2... from tab_old definition only VK]sK e
5、说明:删除新表 s92SN F}g
drop table tabname 2sahb#e
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6、说明:增加一个列 .L))EB
Alter table tabname add column col type 9\a;75a
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。 "tg?V
7、说明:添加主键: Alter table tabname add primary key(col) pcO0xrI
说明:删除主键: Alter table tabname drop primary key(col) oC1Nfc+
8、说明:创建索引:create [unique] index idxname on tabname(col....)
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删除索引:drop index idxname ffoLCx4o0E
注:索引是不可更改的,想更改必须删除重新建。 vjO@"2YEw
9、说明:创建视图:create view viewname as select statement 5YnTGf&
删除视图:drop view viewname Ce!xa\
10、说明:几个简单的基本的sql语句 '(yjq<
选择:select * from table1 where 范围 05/'qf7P,U
插入:insert into table1(field1,field2) values(value1,value2) E@92hB4D"
删除:delete from table1 where 范围 z3Q#Wmv2
更新:update table1 set field1=value1 where 范围
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! I?Ct@yxhF'
排序:select * from table1 order by field1,field2 [desc] b=Oec%Adx
总数:select count as totalcount from table1 }ujl2uhM
求和:select sum(field1) as sumvalue from table1 /}#@uC
平均:select avg(field1) as avgvalue from table1 ;TTH
最大:select max(field1) as maxvalue from table1 #^eXnhj 9
最小:select min(field1) as minvalue from table1 2H2Yxe7? -
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11、说明:几个高级查询运算词 5 p! rZ
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A: UNION 运算符 2(K@V6j$M
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 8)51p+a
B: EXCEPT 运算符 l"1at eM3
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 QK@[b3-h1
C: INTERSECT 运算符 T6fm`uL&L
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 rJ)8KY>
注:使用运算词的几个查询结果行必须是一致的。 OVa38Aucr3
12、说明:使用外连接 9a3mN(<
A、left outer join: }+ZZO0
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 U@<]>.$
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 ~Rk~Zn
B:right outer join: ud:5_*
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。 VDy\2-b8d
C:full outer join: 'fr~1pmx#3
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。 t p<wMrq<
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二、提升 ;{f4E)t 7
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) PQA}_o
法一:select * into b from a where 1<>1 6PdLJ#LS
法二:select top 0 * into b from a xfADks2w
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) yHjuT+/wM,
insert into b(a, b, c) select d,e,f from b; \S[I:fw#&
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) t @vb3
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 P&}J(;Lbl
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. [ T!0ka
4、说明:子查询(表名1:a 表名2:b) }?^5L7n
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) b&\f 8xZ
5、说明:显示文章、提交人和最后回复时间 {'$+?V"&
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b rs+
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6、说明:外连接查询(表名1:a 表名2:b) (~OP)F).
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c n>\2_$uDI
7、说明:在线视图查询(表名1:a ) @z1pE@7jK
select * from (SELECT a,b,c FROM a) T where t.a > 1; kYnp$8
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 ;X)b=
select * from table1 where time between time1 and time2 Bbzmq
select a,b,c, from table1 where a not between 数值1 and 数值2 &^1{x`Qo=
9、说明:in 的使用方法 l#cG#-
select * from table1 where a [not] in ('值1','值2','值4','值6') {?hpW+1,#
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Ic')L*i7O
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) }\3jcnn
11、说明:四表联查问题: cPbAR'
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 ..... ?3Y~q;I]O
12、说明:日程安排提前五分钟提醒 EEdU\9DH(
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 SKeX~uLz
13、说明:一条sql 语句搞定数据库分页 w$4*/D}Y
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 {dXmSuO
14、说明:前10条记录 /;clxtus
select top 10 * form table1 where 范围 c4Wl^E8
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.) ?{rpzrc!*
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) cbaa*qoU
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 $i]G'fj
(select a from tableA ) except (select a from tableB) except (select a from tableC) =u
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17、说明:随机取出10条数据 !@4 i:,p@
select top 10 * from tablename order by newid() W|4h;[w
18、说明:随机选择记录 S\R5SRE
select newid() +
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19、说明:删除重复记录 w:c9Z=KX
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) G;Py%8
20、说明:列出数据库里所有的表名 4c9a"v
select name from sysobjects where type='U' _(:<l
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21、说明:列出表里的所有的 6'45c1e
select name from syscolumns where id=object_id('TableName') WO!'("
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 iph}!3f
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type %:e.ES
显示结果: nN5fP<H2x
type vender pcs o9]i
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电脑 A 1 "< })X.t
电脑 A 1 X;7hy0Y
光盘 B 2 CRs@x` 5ue
光盘 A 2 l?)!^}Qc
手机 B 3 @RXkj-,eC#
手机 C 3 b!oj3|9
23、说明:初始化表table1 Ge1b_?L_
TRUNCATE TABLE table1 EFn[[<&><t
24、说明:选择从10到15的记录 \qz! v
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc |qz&d=>
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三、技巧 +=K =B
1、1=1,1=2的使用,在SQL语句组合时用的较多 \-8S"
"where 1=1" 是表示选择全部 "where 1=2"全部不选, _o7t| pl~
如: zEk/15
if @strWhere !='' ,{X}C
begin A~({vb'
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ;(&S1Rv9
end i "d&U7Q
else t W}"PKv
begin ;cfPS
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' <S3s==Cg
end &a.A8v)
我们可以直接写成 Z -fiJ75
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere (\UpJlW
2、收缩数据库 G j^*
--重建索引 lc\{47LwZ
DBCC REINDEX aM+Am,n`@
DBCC INDEXDEFRAG B
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--收缩数据和日志 )kD B*(?
DBCC SHRINKDB nrg$V>pD
DBCC SHRINKFILE 2p~}<B
3、压缩数据库 OJiwI)a9
dbcc shrinkdatabase(dbname) lokKjs
4、转移数据库给新用户以已存在用户权限 b3Qk;yz
exec sp_change_users_login 'update_one','newname','oldname' K<q#2G0{
go 6bN8}\5
5、检查备份集 ZI.Czzx\=
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' +Jh1D_+!9
6、修复数据库 h@PE:=
ALTER DATABASE [dvbbs] SET SINGLE_USER Ot`znJU@
GO jN-!1O._G
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK AQwai>eL
GO |k^C-
ALTER DATABASE [dvbbs] SET MULTI_USER 055C1RV%
GO $plqk^P
7、日志清除 >t{-_4Yv?
SET NOCOUNT ON JOH\K0=e
DECLARE @LogicalFileName sysname, u|LDN*#DW
@MaxMinutes INT, 0Wj,=9q
@NewSize INT ]>B4
USE tablename -- 要操作的数据库名 P$Q,t2$A
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 +;-ZU
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 0:`*xix
@NewSize = 1 -- 你想设定的日志文件的大小(M) QP/ZD|/ t1
-- Setup / initialize G*_qqb{B
DECLARE @OriginalSize int
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SELECT @OriginalSize = size nyetK
FROM sysfiles 09qfnQG
WHERE name = @LogicalFileName Y"L |D,ex
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ,0c]/Sd*p
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + pu5%$}dBE
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' IhRdn1&
FROM sysfiles zf>*\pZE
WHERE name = @LogicalFileName ;;6$d{
CREATE TABLE DummyTrans ~ #7@;C<nt
(DummyColumn char (8000) not null) 8@Bm2?$}g
DECLARE @Counter INT, &(lQgi+^!
@StartTime DATETIME, F^Bk @
@TruncLog VARCHAR(255) v: veKA
SELECT @StartTime = GETDATE(), =R<92v
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' }2Tq[rl~s
DBCC SHRINKFILE (@LogicalFileName, @NewSize) z'*"iaX<c
EXEC (@TruncLog) W1521:
-- Wrap the log if necessary. ut#pg+#Q
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 5mS/,fs@
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) k* v${1&
AND (@OriginalSize * 8 /1024) > @NewSize a@J/[$5
BEGIN -- Outer loop. n
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SELECT @Counter = 0 2Z5_@Y
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) w{t]^w:
BEGIN -- update mFeR~Bi>!
INSERT DummyTrans VALUES ('Fill Log') zdw*
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DELETE DummyTrans wX$|(Y}
SELECT @Counter = @Counter + 1 Zl>dBc%
END f >.^7.is
EXEC (@TruncLog) ,"Fl/AjO
END Y'5(exW
SELECT 'Final Size of ' + db_name() + ' LOG is ' + KaX*) P
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + p8 Ao{
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' g)R 2V
FROM sysfiles N6v?Qzvi
WHERE name = @LogicalFileName cg o
DROP TABLE DummyTrans &>B"/z
SET NOCOUNT OFF 8Ihl}aguW
8、说明:更改某个表 jZC[_p;
exec sp_changeobjectowner 'tablename','dbo' JEaTDV_
9、存储更改全部表 d14 n>
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch G$2@N6
@OldOwner as NVARCHAR(128), Oxa8u e?
@NewOwner as NVARCHAR(128) .cHkh^EDY
AS %`QgG
DECLARE @Name as NVARCHAR(128) Q6wa-Y,
DECLARE @Owner as NVARCHAR(128) 8d2\H*a9~
DECLARE @OwnerName as NVARCHAR(128) hNhEA $X5
DECLARE curObject CURSOR FOR {
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select 'Name' = name, Ctn
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'Owner' = user_name(uid) z:$ibk4#h
from sysobjects hO&_VCk
where user_name(uid)=@OldOwner TEh.?
order by name $8xb|S[
OPEN curObject p_(En4QSH
FETCH NEXT FROM curObject INTO @Name, @Owner ]Vmo>
WHILE(@@FETCH_STATUS=0) gO)":!_n W
BEGIN zhm 0J-g
if @Owner=@OldOwner C JER&"em7
begin JXMH7
set @OwnerName = @OldOwner + '.' + rtrim(@Name) lx=tOfj8
exec sp_changeobjectowner @OwnerName, @NewOwner ]%y>l j?Y
end *c [^/
-- select @name,@NewOwner,@OldOwner T=)qD2?
FETCH NEXT FROM curObject INTO @Name, @Owner !\[JWN@v
END ".%d{z}vz
close curObject d#]hqy
deallocate curObject :vX%0|
GO #\`kg#&
10、SQL SERVER中直接循环写入数据 ZX64kk+
declare @i int fIl!{pv[
set @i=1 jw9v&/-
while @i<30 ]ly" K!1,
begin GGhk~H4OP
insert into test (userid) values(@i) 9^ZtbmUf
set @i=@i+1 SJ<v< B
end atF#0*e>
小记存储过程中经常用到的本周,本月,本年函数 yW(|auq
Dateadd(wk,datediff(wk,0,getdate()),-1) S<-nlBs.
Dateadd(wk,datediff(wk,0,getdate()),6) ~bCA8
Dateadd(mm,datediff(mm,0,getdate()),0) C l,vBjl h
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) $xbW*w
Dateadd(yy,datediff(yy,0,getdate()),0) Z.u1Dz
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) jS~Pdz
上面的SQL代码只是一个时间段 -F[@)$L
Dateadd(wk,datediff(wk,0,getdate()),-1) QF\nf_X
Dateadd(wk,datediff(wk,0,getdate()),6) Ei):\,Nv
就是表示本周时间段. Y*PfU+y~
下面的SQL的条件部分,就是查询时间段在本周范围内的: g_`a_0v
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) AB`.K{h
而在存储过程中 ~r!(V;k{
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) *<!q@r<d
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 3V?x&qlP>