WordPress inBuilt function ‘get_query_var()’ is not working

The function get_query_var() is a WordPress function used to retrieve a variable value from the current URL’s query string. If you’re experiencing issues with get_query_var(), there are a few things you can check:

1. Verify you are using it within the appropriate context: get_query_var() is meant to be used within the WordPress loop or in a template file where the global $wp_query object is available.
2. Ensure the variable you are trying to retrieve is present in the query string: get_query_var() retrieves values from the query string, so make sure the variable you’re trying to retrieve is actually present in the URL.
3. Confirm the variable name is correct: Double-check that you’re using the correct variable name when calling get_query_var(). It should match the name used in the URL’s query string.
4. Make sure pretty permalinks are enabled: If you’re using pretty permalinks (human-readable URLs) in WordPress, ensure that they are enabled. Sometimes, issues with get_query_var() can occur if pretty permalinks are not set up correctly.
5. Verify any custom rewrite rules: If you have custom rewrite rules in your WordPress installation, they could potentially affect the behavior of get_query_var(). Ensure that your custom rewrite rules are set up correctly and not causing conflicts.

If the get_query_var() function is not fetching data in WordPress, there could be a few potential reasons and solutions to consider:

1. Verify the Query Variable: Make sure you are using the correct query variable name when calling get_query_var(). Query variables are typically defined in the URL or within custom queries, so you need to ensure that you’re using the exact variable name you expect to retrieve.
2. Confirm Correct Usage: Double-check that you are using the get_query_var() function correctly. The function requires passing the query variable name as a parameter, like this: get_query_var('variable_name'). Ensure that you are passing the correct variable name within the parentheses.
3. Check Query Variable Registration: If you are using a custom query variable, verify that you have registered it properly. WordPress provides the query_vars filter for adding custom query variables. You can use this filter to register your variables before they can be accessed with get_query_var().Here’s an example of how to register a custom query variable named ‘my_variable’:

function custom_query_vars($vars) {
    $vars[] = 'my_variable';
    return $vars;
}
add_filter('query_vars', 'custom_query_vars');

1. After registering the variable, you should be able to retrieve its value using get_query_var('my_variable').
2. Confirm Query Variable Existence: Ensure that the query variable you are trying to retrieve actually exists in the current context. For example, if you’re attempting to retrieve a query variable on a single post page, but the variable is only available on archive pages, you won’t get a value. Check the context in which you are using get_query_var() and ensure the variable is available in that context.
3. Check for Custom Rewrite Rules: If you have custom rewrite rules in your WordPress installation, they might be affecting the availability or structure of query variables. Verify that your rewrite rules are correctly set up to pass the query variable values.
4. Debugging: If none of the above solutions work, consider enabling debugging in WordPress to identify any error messages or warnings related to the issue. You can do this by adding the following lines to your wp-config.php file:

define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', false);

After enabling debugging, try accessing the page again and check the debug.log file in your wp-content directory for any relevant error messages.