Postgre Group by json array列

Question

我很难理解postgres json数组类型。如何通过使用json数组列来完成一个组。例如：

select product, avg(sales) 
from Order 
group by product 

"Error: could not identify an equality operator for type json" 

--Order-- 
id | sales | product     
1 | 36 | ["874746", "474657"] 
2 | 120 | ["874748"] 
3 | 15 | ["874736", "474654"] 

Answer 1

您需要使用jsonb（二进制）9.4+：

select product::jsonb, avg(sales) 
from Order 
group by product::jsonb