Question

I have a html form that sends POST data to php file.
In php I’m making a query to mysql database. In database I have int column that accept null.

The problem is when web form field is empty, I want to save null to database.
I tried to make check before building the query

if (empty($licence))
        $sql_query.="null,r1=";
    else $sql_query.="'".$_POST["licence"]."',r1=";

It’s working. But if user write 0 in the form field, in database will be saved null, which is wrong. If user entered 0, I want to save 0, but if the field is empty I want to save null. How to fix this??
The problem is that if field is empty, 0 will be send as post data…

Answer 1

empty() function(PHP Manual)

Returns FALSE if var exists and has a non-empty, non-zero value. Otherwise returns TRUE.

The following things are considered to be empty:

"" (an empty string)
0 (0 as an integer)
0.0 (0 as a float)
"0" (0 as a string)
NULL
FALSE
array() (an empty array)
$var; (a variable declared, but without a value)

In your case, use:

if (!strlen($licence))
    $sql_query.="null,r1=";
else $sql_query.="'".$_POST["licence"]."',r1=";

instead