我如何在SQL查询中获得多个内部联接

Question

问题是在表中联系联系人可以链接到4家公司 我想显示联系人链接到的所有公司。 第一个内部联接工作正常但我想添加3个内部联接，但我不知道如何使用sql server这样做，因为我的经验是使用MySql 这就是我到目前为止所做的：

select contact.Contact_id, 
       contact.Firstname,
       contact.Abbreviation,
       company.Company,
       company.Company,
       company.Company,
       company.Company,
       contact.Sector,
       contact.Available
FROM contact
INNER JOIN company 
  ON  contact.Company_id1=company.Company_id
  WHERE available =1
  ORDER BY Firstname ASC

Answer 1

怎么样

select <columns>
from contact as ct
join company as cy1 on cy1.company_id = ct.company_id1
join company as cy2 on cy2.company_id = ct.company_id2
join company as cy3 on cy3.company_id = ct.company_id2
join company as cy4 on cy4.company_id = ct.company_id4