Is such a result possible with a query from an SQL database? - mysql

Question

I want to fire a query to get such a result:
[{
id: 1,
brandName: "x"
brandModels: [
{id: 1, modelName: "abc", createdAt: "yyyy-mm-dd"},
{id: 2, modelName: "def", createdAt: "yyyy-mm-dd"},
]
},
{
id: 2,
brandName: "y"
brandModels: [
{id: 4, modelName: "ghi", createdAt: "yyyy-mm-dd"},
{id: 5, modelName: "jkl", createdAt: "yyyy-mm-dd"},
]
}]
Tables Schema
BrandsTable
{id, brandName, brand_id}
ModelsTable
{id, modelName, createdAt}
I guess it's not possible like that? I don't have any experience with text-based databases, but I can well imagine that this can be achieved with a MongoDB. Because ultimately I want to have a js object at the end of the day.

Answer 1

Here's an example but I have not tested it:
SELECT JSON_ARRAYAGG(
JSON_OBJECT(
'id', b.id,
'brandName', b.brandName,
'brandModels', m.modelArray
)
) AS joined_result
FROM BrandTable AS b
JOIN (
SELECT brand_id, JSON_ARRAYAGG(
JSON_OBJECT(
'id', id,
'modelName', modelName,
'createdAt', createdAt
)
) AS modelArray
FROM ModelsTable
GROUP BY brand_id
) AS m USING (brand_id);
Note that I had to assume the ModelsTable also contains a column for brand_id, otherwise there is nothing to use in the join condition.
Read documentation for JSON_OBJECT() and JSON_ARRAYAGG() for more information about how these functions work.