在PHP中使用SQL表达式需要帮助

Question

I am trying to omit a column from updating if the value is empty, but would like it to update if its not empty.

So far I came with the following expression

$foo = NULL;


$query = "UPDATE test SET column1 = IF('{$foo}'='',coloumn1,'' )";
$result = mysqli_query($handle,$query);
if(!$result){
    echo mysqli_error($handle);
}

The problem that I am facing is when I set $foo to an actual value coloumn1 is empty again.

I am not sure why. If anyone can help me understand this, I would really appreciate it! Thanks!

Answer 1

If your value is indeed null (not empty), you might want to consider the use of COALESCE:

UPDATE test SET column1 = COALESCE(?,column1)