比率计算在Cloudera

Question

如何从具有0,1，NULL之一的变量中获取比率，以确保将NULL计为0并获得所有

的比率

sum(COALESCE(call_received, 0)) AS call_received

我认为上面的代码片段应该处理NULL，我应该将它除以什么以确保我考虑到所有内容？

Answer 1

您可以使用COUNT(*)：

SELECT SUM(COALESCE(call_received,0)) AS call_received,
       COUNT(*) AS call_total,
       SUM(COALESCE(call_received,0)) / COUNT(*) AS call_received_ratio
FROM yourTable

COUNT(*)在总计数中包含NULL个，因此没有特别要求。