命名查询无法解析地图

Question

I have this code segement

query := `
        SELECT
            co_username as username,
            co_password as password
        FROM
            servers.co
        WHERE
            co_url = concat('https://', :co_url)
    `

    args := map[string]interface{}{
        "co_url": in.Url,
    }

    rows, err := collectorsConfig.Db.NamedQueryContext(ctx, query, args)
    if err != nil {
        msg := "Error getting co credentials for co '%s': %v"
        log.Error.Printf(msg, in.Url, err)
        return
    }

When runnig this snippet, I get an error like this:

Error getting co credentials for co 'some.random.fqdn': could not find name in map[string]interface {}{"co_url":"some.random.fqdn"}

But if I rework the snippet to be

in.Url = "https://" + in.Url

query := `
            SELECT
                co_username as username,
                co_password as password
            FROM
                servers.co
            WHERE
                co_url = :co_url
        `

Everything works. Is there a reason the named input is not working with the Concat function?

Answer 1

This would depend on what sql library you are using, but when using NamedQuery in many libraries, you must escape any other colons, which you will find how to do in its documentation. For example, sqlx requires you to escape a colon with two e.g.

co_url = concat('https:://', :co_url)