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.


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', '', '=', 'contacts.user_id')
 ->join('orders', '', '=', 'orders.user_id')
 ->select('users.*', '', 'orders.price')
- To perform a "left join" query, use the leftJoin() method, in the same way as the join() method.
$users = DB::table('users')
 ->leftJoin('posts', '', '=', 'posts.user_id')


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')

- Documentation: Laravel - Database: Query Builder

Daily Test with Code Example

Which tag is a block element?
<div> <img> <span>
<div>Web Programming and Development</div>
Which CSS code displays the text underlined?
font-style: italic; text-decoration: underline; font-weight: 500;
h2 {
  text-decoration: underline;
Click on the JavaScript function that can access other function after a specified time.
insertBefore() setTimeout() querySelector()
function someFunction() { alert(""); }
setTimeout("someFunction()", 2000);
Click on the instruction that returns the number of items of a multidimensional array in PHP.
count($array) count($array, 1) strlen()
$food =["fruits" =>["banana", "apple"), "veggie" =>["collard", "pea"));
$nr_food = count($food, 1);
echo $nr_food;       // 6
MySQL Database, Query Builder: Join and Union

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