Loopback: How to query an array of objects?

Question

How do I query an array within loopback 3?

I have the following method:

Driver.reserve = async function(cb) {

    let query = {
        where: {
            preferred_delivery_days: {
                elemMatch: {
                    availability: 0
                }
            }
        }
    };

    return await app.models.Driver.find(query);
};

But I am getting the following error:

code: ER_PARSE_ERROR

errno: 1064

sqlMessage: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''{\"availability\":0}' ORDER BY `id`' at line 1

sqlState: 42000

sql: SELECT 
driver021489826505814413.`first_name`,driver021489826505814413.`last_name`,driver021489826505814413.`gender`,driver021489826505814413.`preferred_delivery_days` FROM `my_driver_table` driver021489826505814413 WHERE driver021489826505814413.`preferred_delivery_days`'{\"availability\":0}' ORDER BY `id`

Here is an example of a database entry:

[
    {
        "day": 5,
        "time": "morning",
        "availability": 0
    }
]

Answer 1

I think it might be hard, since according to the docs :

Data source connectors for relational databases don't support filtering nested properties.

If your project is in the starting phase you may consider to change db to mongo or other no-sql db?