PHP零浮点返回true

Question

I have a field in my mySQL db table of type decimal (15,4)

I've never experienced this before but if the value is 0.0000 my PHP if statement is returning true!

As a sanity check I even did:

if(0.0000) echo "Hello World";

And sure enough, Hello World echo'd out. What the hell is going on? Anybody got any ideas?

Answer 1

If it's a float value coming out from DB it will be treated like a string, not like a numeric value. You can try something this:

if(floatval($value) > 0) { ... }

Where $value contains the value from DB.

Answer 2

I think the problem is you got a string "0.0000" from db but not 0.0000 .

Try again with:

if ((int)$your_value) echo "Hello World";

Answer 3

I don't have this behavior on my PHP version (5.3.3).

I suggest casting the number to bool before doing the check: if ((bool) $float) .

Answer 4

I know it's been a long time since this question was opened but I thought it might help out someone else.

A float is actual an approximation of the Real Number . You will find that not all Real numbers can be represented by a float. This might be the reason why you are getting unexpected results. You should have a read of http://php.net/manual/en/language.types.float.php .

If however you need higher precision you should look at using the BC Math lib's http://php.net/manual/en/ref.bc.php .