can I add conditions inside a SQL query, with Postgres?

Solution for can I add conditions inside a SQL query, with Postgres?
is Given Below:

I’m a beginner with SQL.

Here’s the query I’m currently doing:

let getCandlesSQL =
    $"SELECT
           date_trunc('minute', ts) ts,
           instrument,
           MAX(price) high,
           MIN(price) low,
           (SUM(price * price * quantity) / SUM(price * quantity)) midpoint,
           SUM(price * quantity) volume,
           (SUM(direction * price * quantity) / SUM(price * quantity)) direction

    FROM {tableTradesName}
    WHERE instrument="{instrument.Ticker}" AND ts BETWEEN '{fromTime}' AND '{toTime}'
    GROUP BY date_trunc('minute', ts), instrument
    ORDER BY ts
    LIMIT 4500"

it aggregates a bunch of prices in one minute buckets. I would like to know if it is possible to add fields to SELECT that would represent the result of a condition?

specifically: I have ‘fromTime’ and ‘toTime’ and I would like to have a boolean flag that says if the data aggregated has any values that belong to fromTime <= x <= fromTime + 2s AND toTime – 2s >= x >= toTime

Can this be done?