我想写一个查询,我需要列出客户的名字和他们的地址。我遇到的问题是数据分散到两个表中。Client_Address。我是新的SQL和数据库,所以这可能是一个容易的任务,我不确定。我做了一些研究,并考虑过使用内连接,但不确定如何在我的场景中实现它。客户端表的内容为;
Client (ClientNum, ClientName)
Client_Address的内容为;
Client_Address (ClientNum, addressType, street, city, state, postcode)
我需要编写一个查询,其中包括客户端表中的ClientName,还需要包括Client_Address表中的addressType、街道、城市、州和邮政编码。
期望的输出将是;
clientName, addressType, street, city, state and postcode
见下面我的当前代码:
SELECT clientname, addressType, street, city, state, postcode
FROM client , Client_Address
ORDER BY clientName ASC;
您已经编写了一个叉乘,您还没有指定两个表之间的行是如何关联的。使用合适的连接:
SELECT clientname, addressType, street, city, state, postcode
FROM client AS c
JOIN client_address AS a ON c.clientnum = a.clientnum
ORDER BY clientName
您需要按如下方式应用连接查询:
SELECT C.clientname, CA.addressType, CA.street, CA.city, CA.state, CA.postcode
FROM client AS C INNER JOIN Client_Address AS CA
ON C.clientnum = CA.clientnum
ORDER BY C.clientName ASC