simple oracle SQL question

I hope that I am sending this to the correct place and my sincere apologies if I am going off of the topic. I am working on a very simple oracle SQL query and have been seperated from my SQL guide books (they are 200 miles from my present location). I have a table that stores information about services that are being performed. These services, when created, have a SYSDATE placed in a field called "opendate" and a NULL value placed in the field called "closedate". I am now wanting to retrieve a list of all services that are still open, i.e., have no closedate. I tried the following two commands to no avail:

SELECT * FROM tktmaster WHERE closedate='NULL';

and

SELECT * FROM tktmaster WHERE closedate=' ';

There is probably something very simple that I have forgotten but without my SQL reference, I'm lost. Thanks for any assistance that anyone may be able to provide.

Brad McBride Received on Mon Dec 07 1998 - 09:09:27 CST