Question

I would like to write a select where I show the value of the field as normal except when the field is null. If it is null I’d like to show a special text, for example “Field is null”. How would I best do this?

// Oracle newbie

Answer 1

I like to use function COALESCE for this purpose. It returns the first non-null value from given arguments (so you can test more than one field at a time).

SELECT COALESCE(NULL, 'Special text') FROM DUAL

So this would also work:

SELECT COALESCE(
   First_Nullable_Field, 
   Second_Nullable_Field, 
   Third_Nullable_Field, 
   'All fields are NULL'
) FROM YourTable