Question

表1：承包商

Contractor_No; -- PK
Contractor;

表2：合同

Contract_No;   -- PK
ProjDesc;
Contractor_No; -- FK

如何通过将这两个表与Contractor（来自表1），Contract_No，ProjDesc（表2）连接起来来检索数据？

我的SQL语句：

select a.Contractor, b.ProjDesc
from Contractors a, Contracts b
join Contractor a on a.Contractor_No = b.Contractor_No and b.Contract_No='1234';

Answer 1

您有一些语法错误：

SELECT a.Contractor
     , b.ProjDesc
FROM Contractors a 
JOIN Contracts b ON a.Contractor_No = b.Contractor_No 
                AND b.Contract_No = '1234'

Answer 2

select a.Contractor,
       b.ProjDesc
from   Constractors a
       inner join contracts b on
        a.contractor_no = b.contractor_no
where  b.contract_no = '1234'

如何使用别名和条件连接2个表

2 个答案: