如何使用case语句对数据进行排序-使用MySQL？

Question

I have a query but I want to order the data as the following:

1. status (so I have the records with status = 1 on the top and status 2 at the bottom)
   

2. if the records have status = 1 then order them as the following
   a) CASE WHEN i.assigned_to = '.USER_ID.' THEN 0 ELSE 1 END CASE WHEN i.assigned_to = '.USER_ID.' THEN 0 ELSE 1 END
   b) CASE WHEN (i.approved_by > 0 OR i.approved_on IS NOT NULL) THEN 0 ELSE 1 END
   c) i.priority DESC
   d) i.created_on ASC
   

3. if the records have status = 2 then order the records by completed_on DESC
   

This is my current syntax but I can't figure out how to split the order

ORDER BY
  i.status ASC,
  CASE WHEN i.assigned_to = '.USER_ID.' THEN 0 ELSE 1 END,
  CASE WHEN (i.approved_by > 0 OR i.approved_on IS NOT NULL) THEN 0 ELSE 1 END,
  i.priority DESC,
  i.created_on ASC

My query currently order all the records by a) CASE WHEN i.assigned_to = '.USER_ID.' THEN 0 ELSE 1 END b) (CASE WHEN (i.approved_by > 0 OR i.approved_on IS NOT NULL) THEN 0 ELSE 1 END) c) i.priority DESC d) i.created_on ASC

and I want it to order by those only if the status = 1 otherwise order by completed_on DESC

Answer 1

Try:

ORDER BY
  i.status ASC,
  CASE WHEN i.assigned_to = '.USER_ID.' and i.status = 1 THEN 0 ELSE 1 END,
  CASE WHEN (i.approved_by > 0 OR i.approved_on IS NOT NULL) and i.status = 1 
       THEN 0 ELSE 1 END,
  CASE WHEN i.status = 1 THEN i.priority END DESC,
  CASE WHEN i.status = 1 THEN i.created_on END ASC,
  CASE WHEN i.status = 2 THEN i.completed_on END DESC