Question

我对某些MySQL连接执行操作的理解有点分散。

我有多个表，ALM_RECORDS有ID，ALM_PHONES，ALM_ADDRESS都有一列RecordsID，与ALM_RECORDS的ID列相关。

基本上我需要根据此ID从所有3个表中提取。下面是我的查询，但它不断地将重复的条目返回三次。

SELECT a.ID, a.FIRST_NAME, a.LAST_NAME, 
       b.RecordID, b.PHONESID, b.PhoneType, b.NUM,        
       c.RecordID, c.address_block, c.city, c.state, c.post_code, c.country
FROM ALM_RECORDS a
    LEFT JOIN ALM_PHONES b
        ON a.ID = b.RecordID
    LEFT JOIN ALM_ADDRESS c
        ON a.ID = c.RecordID
WHERE a.ID = "123456"

结果应该是：

123456 - John - Smith - Business - 111.222.3333 - address etc..
123456 - John - Smith - Home     - 444.555.6666 - address etc..

但我得到的是：

123456 - John - Smith - Business - 111.222.3333 - address etc..
123456 - John - Smith - Business - 111.222.3333 - address etc..
123456 - John - Smith - Business - 111.222.3333 - address etc..
123456 - John - Smith - Home     - 444.555.6666 - address etc..
123456 - John - Smith - Home     - 444.555.6666 - address etc..
123456 - John - Smith - Home     - 444.555.6666 - address etc..

有人可以向我解释我在这里缺少什么吗？我应该使用不同类型的加入吗？

Answer 1

SELECT a.ID, a.FIRST_NAME, a.LAST_NAME, 
       b.RecordID, b.PHONESID, b.PhoneType, b.NUM,        
       c.RecordID, c.address_block, c.city, c.state, c.post_code, c.country
FROM ALM_RECORDS a
    LEFT JOIN ALM_PHONES b
        ON a.ID = b.RecordID
    LEFT JOIN ALM_ADDRESS c
        ON a.ID = c.RecordID
WHERE a.ID = "123456" GROUP BY b.NUM

MySQL连接导致重复

1 个答案: