如果更新值是特定字符串，则跳过以更新表字段

Question

Can I check if the update value is N , then skip this field?

Should it be done at the code of PHP or MySQL?

the flow is:

BEFORE

update store set book1 = 'Y', book2 = 'Y', book3 = 'N', book4 = 'N', book5 = 'N' where id = 1;

AFTER

update store set book1 = 'Y', book2 = 'Y' where id = 1;

Because book3, book4 and book5 will be updated to the value of N , so I skip this fields

Answer 1

This is a very open ended question. It depends how you are building the SQL code for your script, but if you want to change the SQL then doing it in PHP will be your best bet.

As a quick example, you could do something like this:

$books = array ( 'book1' => 'Y',
                'book2' => 'Y',
                'book3' => 'N',
                'book4' => 'N',
            );

$updates = array();         

foreach ($books as $book => $value) {
    if ($value != 'N') {
        $updates[] = "$book  = '$value'";
    }
}

$update = implode(', ', $updates);
$query = 'update store set '.$update.' where id =1;';