laravel queries several fields

Querying the database is a very common operation when developing Laravel applications, especially for web applications that need to present large amounts of data. However, sometimes we only need to select some specific columns instead of all columns in the entire table. This article will introduce how to query several fields in Laravel.

Using the query builder

Laravel provides a powerful query builder that can help us interact with the database conveniently. We can use the select method to limit the columns we need.

For example, we have a users table, which contains three fields: id, name and email. If we only need to select two of these fields, we can write:

$users = DB::table('users')->select('name', 'email')->get();

In this example, we specify name and # using the select method ##email column. The returned $users object will contain only these two columns.

Of course, we can also choose to use

select to select all columns, and then use the exclude method to exclude the columns we don’t need. For example:

$users = DB::table('users')->select('*')->exclude('id')->get();

In this example, we first use the

select method to select all columns, and then use the exclude method to exclude id List. The returned $users object will only contain the name and email columns.

Using Eloquent

Eloquent is an ORM (Object Relational Mapping) tool in Laravel that can help us operate databases in PHP more conveniently. Eloquent has a similar approach to the query builder that allows us to include only the required columns in the query.

For example, we can create an Eloquent model named

User, which corresponds to the users table:

namespace App;

use IlluminateDatabaseEloquentModel;

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

Then, we can use

select method to include only the required columns:

$users = User::select('name', 'email')->get();

Or use the

exclude method to exclude unwanted columns:

$users = User::exclude('id')->get();

These methods are consistent with query construction The methods provided by the server are very similar.

Conclusion

Querying the database is a common operation, and in Laravel we can easily limit the columns we need using the query builder and Eloquent models. Not only does this reduce the amount of data transferred, it also improves the performance of our application. Hope this article is helpful to you.

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