Laravel's database query builder provides a convenient, fluent interface to creating and running database queries.
- It uses PDO parameter binding to protect your application against SQL injection. There is no need to clean strings passed as bindings.
Joins
To perform a basic "
inner join", you may use the
join() method on a query builder instance.
The first argument is the name of the table you need to join to; the remaining arguments specify the relation of the columns for the join.
- You can join to multiple tables in a single query:
$users = DB::table('users')
->join('contacts', 'users.id', '=', 'contacts.user_id')
->join('orders', 'users.id', '=', 'orders.user_id')
->select('users.*', 'contacts.email', 'orders.price')
->get();
- To perform a "
left join" query, use the
leftJoin() method, in the same way as the
join() method.
$users = DB::table('users')
->leftJoin('posts', 'users.id', '=', 'posts.user_id')
->get();
Unions
To "
union" two queries together, create an initial query and use the
union() method to union it with a second query.
$first = DB::table('users')->whereNull('first_name');
$users = DB::table('users')->whereNull('last_name')
->union($first)->get();
- Documentation:
Laravel - Database: Query Builder
Daily Test with Code Example
HTML
CSS
JavaScript
PHP-MySQL
Which meta tag provides a short description of the page?
<meta content="..."> <meta description="..."> <meta http-equiv="..."><meta name="description" content="70-160 characters that describes the content of the page" />
Which CSS property is used to stop the wrapping effect of the "float"?
clear text-align position#some_id {
clear: both;
}
Click on the method which gets an array with all the elements in the document that have a specified tag name.
getElementsByName() getElementById() getElementsByTagName()var divs = document.getElementsByTagName("div");
var nr_divs = divs.length;
alert(nr_divs);
Indicate the PHP function which returns the number of elements in array.
is_[) count() strlen()$arr =[7, 8, "abc", 10);
$nri = count($arr);
echo $nri; // 4