在查询中使用 JOIN 时，Laravel. Json 转换为数组的列作为字符串返回

Question

Laravel 8. I have two tables(models) ' employees ' and ' positions '. In a model ' employees ' I have a casts:

protected $casts = [
     'academic_post' => 'array'
];

academic_post is stored as a JSON. When I`m getting positions, joining them with employees:

$employees = DB::table('positions')
    ->select('employees.*', 'positions.*')
    ->where('department_tag', '=', $this->department_tag)
    ->leftJoin('employees', 'positions.email', '=', 'employees.email')
    ->get();

Problem : as employees table is used in leftJoin , $employees[0]->academic_post gives a string, not being casted as an array. I know I can make a foreach loop and use json_decode for each row to make an array, but why array casting is not working in this kind of query? If Im using for example: Employee::find(1); - Im getting column academic_post as array , as expected . I just want it to work stright from a query, not using any kind of loop. Any suggestions?

Answer 1

You can get your json fields using mysql function JSON_EXTRACT

assuming your json string is like: {"name": "John", "age": 30}

then you can get each field like this:

$employees = DB::table('positions')
    ->select('employees.*', 
             'positions.*',
             DB::raw('JSON_EXTRACT(employees.academic_post, \'$.name\') as name'),
             DB::raw('JSON_EXTRACT(employees.academic_post, \'$.age\') as age'),
      )
    ->where('department_tag', '=', $this->department_tag)
    ->leftJoin('employees', 'positions.email', '=', 'employees.email')
    ->get();