如何在MySQL中获取Filled(没有Empty和not Null值的列)columns Count

Question

有人能帮我获得已填充MySQL列的计数吗？

例如：我的表格结构：

ID	FName	LName
1	ABC	NULL
2		XYZ

所以，在搜索了一两个小时之后。

我使用这个作为我的解决方案，但我不确定重新分级优化是否好。这是我正在使用的：

function ranking_mechanism( $currentUserID ){
global $wpdb;
$rank = 0;
$results = $wpdb->get_row(
$wpdb->prepare('SELECT * FROM TABLE WHERE ID=%d', $currentUserID)
); 
$finalArr = (array) $results; // Convert $results as Array(to perform iteration), it(WordPress DB Query) typically return Object by Default 
foreach ( $finalArr as $key => $Table ) {
if( $finalArr[$key] == '' || $finalArr[$key] == 'NULL' ){
// Nothing to do 
}else{
$rank = $rank+1; // Increase Rank If Found Value
}
return $rank;
}

SELECT ID,   (ID IS NOT NULL) /* assuming that ID is numeric and cannot be empty string */
+ (FName <> '' AND FName IS NOT NULL) 
+ (LName <> '' AND LName IS NOT NULL) AS `Count`
FROM source_table
-- WHERE ID = ???