syncrow-data/fact_thermostat_duration/fact_thermostat_duration.sql

WITH avg_set_temp AS (
    -- Step 1: Compute the average set temperature per device per hour
    SELECT 
        device.uuid AS device_id,
        device.space_device_uuid AS space_id,
        event_time::date AS date,
        DATE_PART('hour', event_time) AS hour,
        AVG("device-status-log".value::INTEGER) AS avg_set_temp
    FROM device
    LEFT JOIN "device-status-log"
        ON device.uuid = "device-status-log".device_id
    LEFT JOIN product
        ON product.uuid = device.product_device_uuid
    WHERE product.name = 'Smart Thermostat'
    AND "device-status-log".code = 'temp_set'
    GROUP BY 1,2,3,4
),

avg_set_temp_filled AS (
    SELECT 
        device_id,
        space_id,
        date,
        hour,
        avg_set_temp,
        COALESCE(
            avg_set_temp, 
            LAG(avg_set_temp) OVER (
                PARTITION BY device_id 
                ORDER BY date, hour
            )
        ) AS filled_avg_set_temp
    FROM avg_set_temp
)

SELECT 
    d.uuid AS device_id,
    d.space_device_uuid AS space_id,
    l.event_time::date AS date,
    DATE_PART('hour', l.event_time) AS hour,
    CASE WHEN l.code = 'temp_current' THEN l.value END AS current_temp,
    f.filled_avg_set_temp
FROM device d
LEFT JOIN "device-status-log" l
    ON d.uuid = l.device_id
LEFT JOIN product p
    ON p.uuid = d.product_device_uuid
LEFT JOIN avg_set_temp_filled f
    ON f.device_id = d.uuid
    AND f.date = l.event_time::date 
    and f.date = l.event_time::date AND f.hour <= DATE_PART('hour', l.event_time)
WHERE p.name = 'Smart Thermostat'
and l.code = 'temp_current'
ORDER BY d.uuid, l.event_time;