多个字段取最大值、最小值、首个非空值
-- 多个值取最大和最小 select least(1,2,3,0,4,5) as min,greatest(1,2,3,0,4,5) as max;
+------+------+--+ | min | max | +------+------+--+ | 0 | 5 | +------+------+--+
select coalesce(null,null,1,null,0) as value1,coalesce(null,0) as value2,nvl(null,0) as value3;
+---------+---------+---------+--+ | value1 | value2 | value3 | +---------+---------+---------+--+ | 1 | 0 | 0 | +---------+---------+---------+--+