How to perform database query based on array in php

In web development, using database queries is a very important skill. Sometimes, we need to query the data in the database that meets certain conditions and process and display the results. In this case, it would be very convenient if we could query based on the array.

In PHP, you can use MySQLi extension or PDO extension to complete database query operations. Today we will use the MySQLi extension to demonstrate how to perform database queries based on arrays.

First, suppose we have a table called "users" with fields such as id, name, age, and gender. We need to query the information of all users whose age is greater than or equal to 18 and whose gender is female. We can store these conditions in an array as shown below:

$conditions = [
    'age' => '>=18',
    'gender' => 'female'
];

Next, we can use the mysqli_real_escape_string() function in the MySQLi extension to escape the values ​​in the array to prevent SQL injection attacks .

foreach($conditions as $key => $value) {
    $value = mysqli_real_escape_string($connection, $value);
    $conditions[$key] = "$key $value";
}

By looping through all the keys and values ​​in the array, we escape and combine each condition into a string similar to "key 'value'", which will be used as a SQL query statement part of the WHERE clause.

Next, we can use the implode() function to concatenate the conditional array into a complete WHERE clause. The query code is as follows:

$whereClause = implode(' AND ', $conditions);
$query = "SELECT * FROM users WHERE $whereClause";

$result = mysqli_query($connection, $query);

// do something with the query result

This query uses the WHERE clause to filter the data in the users table and only displays data that meets the conditions.

In summary, database query based on an array requires the following steps:

1. Store the query conditions in an array.
2. Use the mysqli_real_escape_string() function to escape the values ​​in the array to prevent SQL injection attacks.
3. Loop through the keys and values ​​in the array and combine them into part of the WHERE clause.
4. Use the implode() function to connect the conditions in the WHERE clause into a complete string.
5. Use query statements to query the database.
6. Process query results.

The above are the relevant operation methods for database query based on arrays. I hope to be helpful.

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