Dynamic query displaying

[ks129]

I want to make command that executes query and output this in format:

col1=val1 col2=val2 ...

(this is Serenity Discord bot command):

#[command]
#[description("Fetch single row from DB table.")]
#[owners_only]
async fn row(ctx: &Context, msg: &Message, args: Args) -> CommandResult {
    // First we have to get PostgreSQL pool.
    let data = ctx.data.read().await;
    let pool = data.get::<PostgresPool>().expect("Unable to get PostgreSQL pool.");

    // After this, we can execute query.
    let raw_result: sqlx::postgres::PgRow = sqlx::query(args.rest()).fetch_one(pool).await?;

    let mut result = String::new();
    for column in raw_result.columns().iter() {
        let value: &str = raw_result.get(column.name());
        result.push_str(format!("{}={:?} ", column.name(), value).as_str());
    }

    msg.channel_id.send_message(ctx, |m| {
        m.embed(|e| {
            e.title("Query result");
            e.description(format!("```{}```", result));

            e
        });

        m
    }).await?;

    Ok(())
}

Biggest problem of this is that I don't know to what type to convert it value. I want that this convert value to that type what is equal with column's PostgreSQL type. How to do this?