How to use conditions to filter thinkphp related queries

When developing with thinkphp, you often encounter situations where you need to use related queries. When performing related queries, conditions are a point that we often need to pay attention to.

This article will introduce how to use conditions to filter when performing related queries in thinkphp.

1. Define the association in the model

When performing an associated query, you first need to define the association in the model. Here we take a one-to-one relationship as an example. First, define a User model, which contains a hasOne association:

class User extends Model
{
    protected $table = 'users';

    public function profile()
    {
        return $this->hasOne('Profile');
    }
}

In the above code, we define a hasOne association named profile, which is associated with a model named Profile. In the Profile model, you need to define the belongsTo association:

class Profile extends Model
{
    protected $table = 'profiles';

    public function user()
    {
        return $this->belongsTo('User');
    }
}

In the above code, we define a belongsTo association named user, which is associated with a model named User.

2. Perform related queries

After defining the relationship, we can perform related queries in the controller. The query statement is as follows:

$users = User::with(['profile' => function($query){
    $query->where('age', '>=', 18);
}])->select();

In the above code, we use the with method to perform related queries. Among them, the first parameter passes the association we want to query, and the second parameter is a callback function used to impose some additional conditional restrictions on this query.

In the above code, we used the where method to filter the age attribute of the profile model and only query records whose age is greater than or equal to 18.

3. Chained operation conditions

In addition to passing the callback function in the with method to limit the query conditions, you can also perform chained operation conditions when performing related queries. . For example, the following code implements a query for users whose age is greater than or equal to 18 in the user table, and for records whose address is not empty in their profile records:

$users = User::where('age', '>=', 18)
             ->with(['profile' => function($query){
                 $query->where('address', '<>', '');
             }])
             ->select();

In the above code, we first use the where method Query conditions are restricted for the User model. Then, we used the callback function in the with method to restrict the query conditions of the profile model.

4. Summary

When performing related queries in thinkphp, we can use the with method to perform related queries, and pass callback functions or chain operation conditions to Query results can be further restricted and filtered.

Of course, when performing related queries, we also need to pay attention to some other details, such as the definition of related relationships, the writing of query statements, etc. In the actual development process, we need to perform flexible operations according to specific circumstances.

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