如何在Laravel PHP中内部联接表

Question

I have this query which is 我有这个查询

SELECT * FROM books b 
INNER JOIN categories c ON b.category_id = c.id 
WHERE c.category_name = 'Comics'

thus is passed by parameter 因此通过参数传递

SELECT * FROM books b 
INNER JOIN categories c ON b.category_id = c.id 
WHERE c.category_name = ?

I tried in Laravel like this 我这样在拉拉维（Laravel）试过

writer::join('categories','categories.id','=','writers.category_id')
  ->where('categories.category_name','Comics')
  ->get();

And with parameter 并带有参数

writer::join('categories','categories.id','=','writers.category_id')
  ->where(['categories.category_name' => $cat])
  ->get();

I didn't get any data in Laravel! 我没有在Laravel中获得任何数据！ Is there any mistake I am doing? 我有什么错误吗？

Answer 1

Try this instead: 尝试以下方法：

writer::join('categories','categories.id','=','writers.category_id')
->where([
  ['categories.category_name', '=', $cat]
])->get();

or 要么

writer::join('categories','categories.id','=','writers.category_id')
->where('categories.category_name', $cat)
->get();