连接表上的SQL Case Condition

Question

我需要使用case条件修改这个sql，我需要所有模型来回显但是如果where条件满足则只回显tw。最好的方法是什么？

SELECT * FROM model
LEFT OUTER JOIN tw
ON model.model_name=tw.model
WHERE tw.completed = 1 AND tw.stock = 0
ORDER BY model.id

Answer 1

我认为您只需将where条件移至on子句：

SELECT m.*, t2.*
FROM model m LEFT OUTER JOIN
     tw
     ON m.model_name = tw.model AND
        tw.completed = 1 AND tw.stock = 0
ORDER BY m.id;