关于SQL三张表的按条件查询查询

[yichen520sen]

三张表company，Phone，Visit

company表字段
Id Name，adrress，Phone，Moblie
Phone表字段
Id ,CompanyId（外键）, appdate,appContent,
Visit表字段
Id,CompanyId（外键）,visitDate,visitContent.


我要在页面上按条件查询；company的Name，Phone的appdate，，Visit的visitDate 三个条件查询
怎么写这个SQL语句 GridView显示 Name，adrress，Phone，Moblie，appdate，visitDate的值

请高手指点

[chuifengde]

select a.name,adrress,phone,moblie,b.appdate,c.visitdate
from company a inner join Phone b on a.id=b.companyid 
inner join visit c on a.id=c.companyid

[--小F--]

select
 a.name,adrress,phone,moblie,b.appdate,c.visitdate
from
 company a ,Phone b mvisit c 
where
 a.id=b.companyid 
and
 a.id=c.companyid

[dawugui]

select t1.name , t1.adrress,t1.phone,t1.mobile,t2.appdate,t3.visitDate
from company t1 , Phone t2,Visit t3
where t1.Id = t2.CompanyId and t1.id = t3.CompanyId

[dawugui]

--如果你能确保各表所有数据都能关联.

select t1.name , t1.adrress,t1.phone,t1.mobile,t2.appdate,t3.visitDate
from company t1 , Phone t2,Visit t3
where t1.Id = t2.CompanyId and t1.id = t3.CompanyId

--否则需要使用下面的语句

select t1.name , t1.adrress,t1.phone,t1.mobile,t2.appdate,t3.visitDate from company t1 
left join Phone t2 on t1.Id = t2.CompanyId 
left join Visit t3 on t1.id = t3.CompanyId

select t1.name , t1.adrress,t1.phone,t1.mobile,
       appdate = (select appdate from Phone t2 where t2.CompanyId = t1.Id),
       visitDate = (select visitDate from Visit t3 where t3.CompanyId = t1.Id)
from company t1

[daishaodong]

只查询出匹配的记录，用inner join 加on，或2楼的方法，

若左表的表要列出全部记录，用left inner 加 on条件

[yichen520sen]

那三张表删除呢。。。

[yichen520sen]

删除一个客户Id其他两张表的内容全都删除。。。请高手写个高效率的SQL语句，，，要是数据量50000以上，普通的SQL语句会瘫痪的。。