[firebird-support] compaing NULL values like NEW,COLUMN and OLD.COLUMN in triggers

[sir_wally_lewis]

We need to do a lot of checking in update triggers to check for value changes.

ie if( OLD.FIELD1 <> NEW.FIELD1 )OR( OLD.FIELD2 <> NEW.FIELD2 )THEN
      DO SOMETHING;

However if either value is NULL then the response will be NULL.

Is there an easy way to compare values, taking into account these values may be 
NULL?

Kind Regards,

Robert.