使用标准的SQL CASE:

Use a Standard SQL CASE:

SELECT hook_type, 
   CASE hook_type
      WHEN 0 THEN 'OFFER'
      WHEN 1 THEN 'ACCEPT'
      WHEN 2 THEN 'EXPIRED'
   END AS hook_name,
   COUNT(*) AS number_of_exchange_activities 
FROM `exchange` 
GROUP BY hook_type