What happens if null?

Jon12345

What happens if one or more of my variables are not set or empty when I use an INSERT statement for a mySQL db?

$query="INSERT INTO log (ipaddress,date,time,kid,sid) VALUES ('$ipaddress','$date','$time','$kid','$sid')";

Will the INSERT statement fail or does it just leave a blank in that field?

Piranha

Have you echoed the $query string? Did it look ok? Have you tried it out? This time I will answer as good as I can, but please try it yourself next time. I don't know how it is in all cases, but I can give you some information at least.

If the value is a string it will work. It does not matter if the column allows null or not since even an empty string is a string and have a value.

When it comes to other datatypes (int, double, boolean, date, time, timestamp and so on) I have no idea what will happen. The best thing is probably to just try it out, then you will know.

Rodney_H_

You can check for empty BEFORE inserting data. (You can do this the same time you validate/filter user input and convert POST data to usable/clean variables...)

IF empty, you can set a default value to your variable.

NogDog

PHP will put nothing in the string at that point, so you'll just have an empty pair of quotes in the SQL (if it's not quoted, then you may get an SQL error at that point -- I'm not positive though). Also, PHP will raise a notice-level warning if the variable is unset (as opposed to set with a value of NULL or an empty string).