arrays - Postgres 按 json 数组列分组

Question

我很难理解 Postgres json 数组类型。如何使用 json 数组列进行分组。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