php - 如何在 laravel php 中内连接表

Question

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'

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 = ?

我在 Laravel 中尝试过这样

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

并带有参数

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

我在 Laravel 中没有获取任何数据!我有什么错误吗？

Answer 1

试试这个:

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

或

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