[Resolved] A simple problem?

[harleyh]

I have a problem that I have been staring at all day and just can't figure it out. Here is what I am trying to execute;

$query="SELECT * FROM codes WHERE code = '$_POST

' && used <> 'x'";

 $result = mysql_query($query) or die (mysql_error());
  if (mysql_num_rows($result) <> 0)
  { //allow discount  }

here is the database;

code           used  

harley08    

harley88    x 


If I remove the && used <> 'x' and look for coed='harley08', then I get one row returned, but with it in there i get 0 rows?????? Both fields are character fields.

Any ideas???

[devinemke]

what exactly is the problem? mySQL is returning the number of rows that matches your search criteria.

[harleyh]

No it doesn't. For the row that has code=harleyh08 the filed 'used' is empty.

So SELECT * FROM codes WHERE code = 'harley08' && used <> 'x'
should return for me that first row. Shouldn't it?

[devinemke]

i think you may be getting confused as to the difference between empty and NULL. if the "used" column in your table allows NULL values and defaults to NULL then it is not empty, it is NULL. when you compare strings such as you are then "x" does not explicitly mean NOT NULL. you might want to do some reading on how mySQL deals with NULL.

[harleyh]

yup, it was that darn NULL thing.

THX