[TIP] Use COALESCE instead of nested IFNULL calls.

[Ivan Smahin]

Hello Valentina,

  Here is just a tip.
  
  Example:
  
  SELECT
        IFNULL(f1, IFNULL(f2,f3)) as 'ff'
  FROM
      t1

  Here we just need to get first not-null value using field-order - f1,f2,f3.

  The issue seems to be a little bit bulky.
  You can use COALESCE instead of. It seems more clear and concisely.
  Look:

  SELECT
        COALESCE(f1, f2, f3) as 'ff'
  FROM
      t1
  

-- 
Best regards,
 Ivan                          mailto:IvanSmahin at public.kherson.ua