我的数据库中有一个json列（是对象数组），其中包含与此类产品相关的许多类别：
[
{
"id": 1,
"name": "Category X"
},
{
"id": 2,
"name": "Category Y"
},
...
]
我需要将以下PostgreSQL查询转换为活动记录查询：
SELECT * FROM products p, json_array_elements(p.category) as data
WHERE data ->>'name' = 'Sport';
我尝试过的一些查询：
sports = Product.where("category ->>'name' = ?", "Sport")
这将返回一个空数组（这是错误的，因为我的数据库中有运动类别的记录）
sports = Product.where("category @> ?", [{name: "Sport"}])
Which raises: TypeError: can't quote Hash
sports = Product.where("category @> ?","{name: 'Sport'}")
Which raises: ERROR: operator does not exist: json @> unknown
and the Hint: No operator matches the given name and argument type(s). You might need to add explicit type casts.
所以我尝试了：
sports = Product.where("category @> ?", "[{'name': 'Sport'}]")
和
sports = Product.where("category @> ?", "[{'name': 'Sport'}]".to_json)
和其他一些查询都没有成功。
These links: PostgreSQL functions-json active record querying didn't help much.
