Summarize some methods of querying data in Laravel5

Laravel is a popular PHP framework that provides powerful database management tools so that developers can manage databases quickly and efficiently. In this article, we will introduce how to query data in Laravel5.

First, we need to ensure that the table to be queried is set up in the Laravel project. After creating the table in the database, we can use ORM (Object Relational Mapping) to query the data. ORM can map each row of data in the database into an object, which allows us to manipulate data in an object-oriented manner.

Let’s demonstrate some methods of querying data in Laravel5:

1. Basic query

In Laravel5, we use the Eloquent builder to execute the basics Inquire. It is Laravel's ORM through which we can do basic queries easily.

The following is an example of querying the users table:

$users = DB::table('users')->get();

In the above code, we use the DB class and specify the name of the table to be queried. Then, we call the get() method, which returns the Result object, which contains the result set obtained by the query.

2. Conditional query

In Laravel, we can use the where() method to add query conditions. The following is an example of querying users who meet specific conditions in the users table:

$users = DB::table('users')->where('name', 'John')->get();

In the above code, we specify the query conditions in the where() method, and the results obtained by the query will include users whose name field is John. .

In Laravel, many other methods are provided to add query conditions, such as orWhere(), whereIn(), etc.

3. Aggregation function query

In Laravel, we can use aggregate functions to query the database. The following is an example of calculating the oldest user in the users table:

$maxAge = DB::table('users')->max('age');

In the above code, we use the max() method provided by Laravel to calculate the maximum value of the age field.

In addition to the max() method, Laravel also provides many other aggregate functions, such as sum(), count(), etc.

4. Joint table query

In Laravel, we can use the join() method to perform a joined table query. The following is an example of querying information in the users table and orders table:

$data = DB::table('users')
            ->join('orders', 'users.id', '=', 'orders.user_id')
            ->select('users.*', 'orders.price')
            ->get();

In the above code, we use the join() method to specify the join table conditions, and then use the select() method to select the items to be queried. Field, the get() method obtains the query results.

The above are some methods of querying data in Laravel5. Laravel provides rich ORM operations, making it easier for us to operate the database. I hope this article can help you better understand Laravel's ORM operations.

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