1、简单Case函数
case a.if_adddrivinglicense when '是' then (b.typename || '/' || a.new_drivinglicens) else b.typename end
2、Case搜索函数
case when a.tempaddrnumb is null then null else '居住证' end
例:
select a.employee_name,(case when a.tempaddrnumb is null then null else '居住证' end) as tempaddrname from oms_employee a where a.employee_name like '%彪%';