Comparisons with NULL
Functions with NULL
COALESCE to the rescue
Instruction
Good. COALESCE failed, as you can see. How can we cope with this? We can always convert any type to varchar:
COALESCE(CAST(price AS varchar),'--');
Let's give it a go.
Exercise
Second time success! Modify the template to select the product name and launch_date. Show 'no date' when there is no launch_date. Add CAST so that COALESCE works properly.
Stuck? Here's a hint!
Use COALESCE(CAST(launch_date AS varchar), 'no date').
