mysql - SQL 连接 : Select rows with no match in second table

Question

我试图连接两个表，同时仍然从表 A 中获取结果，即使表 B 中没有匹配的记录。我认为 where 子句导致了问题，但我似乎无法修复它。

SELECT a.id, a.title, a.validation, b.data 
FROM client_option_detail AS a LEFT OUTER JOIN client_data AS b 
ON a.id = b.client_option_detail_id 
WHERE a.client_option_id = ?
AND (b.client_id IS NULL OR b.client_id = ?)

更新:数据库布局

client_option       client_option_detail 
-------------       ------------------- 
id                  id
                    title
                    validation          
                    client_option_id


client          client_data
-------         ------------ 
id              client_id
                client_option_detail_id             
                data

数据库示例:

client_option       client_option_detail 
-------------      ------------------------------------------- 
id                  id | title | validation | client_option_id
-------------      -------------------------------------------
1                  1   | test1 |            | 1  
2                  2   | test2 |            | 1                               
                   3   | test3 |            | 1
                   4   | test4 |            | 2


client              client_data (primary key - client_id + client_option_detail_id)
--------            ------------------------------------------- 
 id                 client_id | client_option_detail_id | data
--------            -------------------------------------------
 1                  1         | 1                       | data1
 2                  1         | 2                       | data2
                    1         | 4                       | data3
                    2         | 3                       | data4
                    2         | 1                       | data5

示例查询:

SELECT a.id, a.title, a.validation, b.data 
FROM client_option_detail AS a LEFT OUTER JOIN client_data AS b 
ON a.id = b.client_option_detail_id 
WHERE a.client_option_id = 1
AND (b.client_id IS NULL OR b.client_id = 1)

所需输出:

    ------------------------------------------- 
     id | title | validation | data
    -------------------------------------------
     1  | test1 |            | data1                                 
     2  | test2 |            | data2
     3  | test3 |            | 

Answer 1

SELECT client_option_detail.id, title, validation, data 
FROM client_option_detail LEFT OUTER JOIN client_data 
ON client_option_detail.id = client_data.client_option_detail_id 

应该没问题。我认为是你的条件有问题。
例如:client_option_detail.client_option_id = ?,?它包含 client_option_detail 中的所有 id 吗？