PHP Warning: mysqli_query(): Couldn't fetch mysqli solution

PHP Warning: mysqli_query(): Couldn't fetch mysqli solution

Recently, many PHP developers have encountered this problem: "Couldn't fetch mysqli" appears when using the mysqli_query() function "Error message. This error message is usually caused by a problem with the database connection. This article will show you how to solve this problem.

Problem Analysis

In PHP, the mysqli_query() function is used to execute mysql query statements. This function is often used to interact with the database. When we call the mysqli_query() function, if the “Couldn’t fetch mysqli” error occurs, it means that the mysqli_query() function cannot access the database connection normally.

The reasons for this situation are very diverse, including but not limited to the following:

1. The database connection is lost or cannot be established successfully.
2. The database account is locked.
3. Insufficient database permissions.
4. The mysqli extension is not enabled in PHP.
5. MySQL service is not started.

Solution

In response to the above situations, we can adopt the following solutions:

1. The database connection is lost or cannot be established successfully

In this case, we need to first check whether the database configuration information is correct. If there is no problem with the configuration information, then we need to check whether the code to establish the database connection in the PHP program is correct and ensure that the user name, password, host, port and other information are filled in correctly. If everything is OK, we can try to restart the server or restart the MySQL service.

2. The database account is locked

If the database account is locked, we need to open the MySQL console, log in with the root account, and check whether there is a problem with the locked account . If the problem is not major, you can unlock the account by changing the account password. If the problem is serious, consider creating a new user.

3. Insufficient database permissions

When we use the mysqli_query() function, if the current database account does not have sufficient permissions to access certain database resources, then "Couldn' t fetch mysqli" error. We need to determine whether the mysqli_query() function requires administrator permissions, and check whether the current account has such permissions. If not, it needs to be solved through authorization.

4. The mysqli extension in PHP is not enabled

If the mysqli extension in PHP is not enabled, we need to enable the mysqli extension module in the PHP.ini file, that is, change "php_mysqli .dll" is added to the configuration starting with "extension". After enabling, you need to restart the PHP service.

5. MySQL service is not started

When the MySQL service is not started, we need to check the operating system service status to confirm whether the service is running normally. If the service is not started, we can manually start the service and check whether the MySQL service is faulty.

Summary

The “Couldn’t fetch mysqli” error often occurs when using the mysqli_query() function because this function cannot access the database connection normally. Solving this problem requires careful analysis and troubleshooting of the cause. You may need to check database connection information, account locking and permissions, mysqli extension module and other aspects. If you encounter this problem, you can troubleshoot it one by one according to the methods described in this article.

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