从一个表中获取全部，从另一个表中获取COUNT

从一个表中获取全部，从另一个表中获取COUNT

您想这样做：

SELECt categories.id, max(categories.slug), count(categories_questions.id) AS numberOfQuestionsFROM categoriesLEFT JOIN categories_questionsON categories.id = categories_questions.category_idgroup by categories.id

在

LEFT JOIN

将确保没有问题类别获得与数= 0上市