左连接如果存在右字段，我如何使用 where

Question

我有两个 table：

用户（查询中使用的字段）->

 |uuid|name|last_name|email|rol        |status|
 |1234|abcd|   abc   |1@2.3|pre-thunder|  1   |
 |5678|efgh|   efg   |4@5.6|pre-thunder|  1   |

和documentation_thunder table（查询中使用的字段）->

|id|id_thunder|doc_type|
|1 |1234      |image   |

我尝试获取左侧的所有记录 table 但另外我还从右侧获取计数 table:

SELECT 
 users.uuid,
 users.email,
 users.name,
 users.last_name, 
 COUNT(documentation_thunder.id) as documentation// i need to know how many documents have the user
FROM users 
LEFT JOIN documentation_thunder
  ON users.uuid = documentation_thunder.id_thunder 
WHERE 
 users.status = 1 AND users.rol = 'pre-thunder' AND (documentation_thunder.doc_type = 'image' OR documentation_thunder.doc_type IS NULL)

此查询仅 returns 第一个用户，但我需要 returns 所有用户，无论是否有文档。

有什么想法吗？我该怎么做？

Answer 1

既然你想为每个用户return一个count，你也应该使用group by。也许这就是您想要的：

SELECT 
 users.uuid,
 users.email,
 users.name,
 users.last_name, 
 COUNT(documentation_thunder.id) as documentation
FROM users 
LEFT JOIN documentation_thunder
  ON users.uuid = documentation_thunder.id_thunder 
WHERE 
 users.status = 1 AND users.rol = 'pre-thunder' AND 
 (documentation_thunder.doc_type = 'image' OR documentation_thunder.doc_type IS NULL)
GROUP BY users.uuid

左连接如果存在右字段，我如何使用 where

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