How to query the result set in PHP and convert it into a one-dimensional array

In PHP, we often need to use data in the database to perform some operations, among which query operations are more common. In the query results, sometimes we only need part of the data and need to use it in the form of an array. In this case, we need to convert the result set into a one-dimensional array. This article will introduce a simple method that can be used to quickly convert the query result set into a one-dimensional array.

Introduction

When we query the database and the result is a two-dimensional array, sometimes we need to use one of the columns as a one-bit array. In this case, we need to use the entire result set Convert to one-dimensional array. The conversion method is as follows:

1. First, we need to perform a query operation. The query operation can be implemented using mysqli or PDO extension in PHP.
   Let us assume that we have successfully queried the required result set.
   The following is a query operation using the mysqli extension:

$mysqli = new mysqli("localhost", "username", "password", "database_name");
$result = $mysqli->query("SELECT column_name FROM table_name");

2. Next, we need to use the while loop in PHP to traverse the query result set and assign the required data Given a one-dimensional array.
   The following is the conversion operation using the mysqli extension:

$array = array();
while($row = $result->fetch_assoc()) {
    $array[] = $row['column_name'];
}

Among them, the fetch_assoc() function is used to obtain the associative array from the result set, the column name is the key name, and the column value is the key value. When converting it into a one-dimensional array, we only need to assign the value of the specified column of each row to the one-dimensional array.

3. Finally, we can operate on the converted one-dimensional array, output or perform other operations on it.

The complete code is as follows:

$mysqli = new mysqli("localhost", "username", "password", "database_name");
$result = $mysqli->query("SELECT column_name FROM table_name");
$array = array();
while($row = $result->fetch_assoc()) {
    $array[] = $row['column_name'];
}
print_r($array);

Advantages

Using this method, we can quickly convert a two-dimensional array into a one-dimensional array to facilitate subsequent operations. . This method has the following advantages:

1. Simple and easy to understand: The code of this method is concise and easy to understand, so it is easy to apply in daily development.
2. High efficiency: This method only needs to obtain the data in the result set one by one through a loop, and requires almost no additional calculations, so it can ensure high efficiency.
3. Scalability: This method can be customized according to actual needs. It can convert the entire result set into a one-dimensional array, or combine and transform multiple columns of data in the result set.

Summary

Through the above analysis, we can see that the application of this method in database development has great advantages. In the actual development process, we only need to encapsulate this method to a certain extent or combine it with other database operations to meet various needs.

It is worth mentioning that in addition to using the mysqli extension in the above example, we can also use the PDO extension in PHP to meet different needs. At the same time, when we use the code, we also need to ensure the robustness and security of the code and try to avoid malicious attacks such as SQL injection.

In PHP development, mastering database operations and query operations is a very important part. I believe that through the introduction of this article, students have mastered how to convert the query result set into a one-dimensional array. I hope it will be helpful to everyone's development.

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