De alias 'Datum' is vanaf daar niet te zien.
Je kunt een paar tabellen gebruiken na WITH, dus ik raad je aan om daar naar de tweede selectie te gaan.
Ik ben niet helemaal zeker van de tabelstructuur van weather.meso, maar door te raden op basis van uw zoekopdracht, zou dit moeten werken:
WITH
forecast_prep AS (
SELECT
date_trunc('day', foretime) :: DATE AS Foredate,
extract(HOUR FROM foretime) + 1 AS foreHE,
lat,
lon,
max(windspeed) as windspeed,
max(as_of) AS as_of
FROM weather.forecast
WHERE date_trunc('day', foretime) :: DATE - as_of >= INTERVAL '16 hours'
GROUP BY Foredate, foreHE, lat, lon
),
tmp AS (
SELECT
meso.station,
meso.lat,
meso.lon,
meso.timestmp,
date_trunc('day', meso.timestmp) :: DATE AS Date,
extract(HOUR FROM meso.timestmp) + 1 AS HE,
CAST(AVG(meso.windspd) AS NUMERIC(19, 2)) AS Actual
FROM weather.meso
GROUP BY station, lat, lon, timestmp, Date, HE
)
SELECT
tmp.station, tmp.Date, tmp.HE, tmp.Actual, forecast_prep.windspeed, forecast_prep.as_of
FROM tmp
INNER JOIN forecast_prep ON (
tmp.lat = forecast_prep.lat
AND tmp.lon = forecast_prep.lon
AND tmp.Date = forecast_prep.Foredate
AND tmp.HE = forecast_prep.foreHE
)
WHERE
(tmp.timestmp BETWEEN '2016-02-01' AND '2016-02-02')
AND (tmp.station = 'KSBN')
GROUP BY
tmp.station, tmp.Date, tmp.HE, forecast_prep.windspeed, forecast_prep.as_of, tmp.Actual
ORDER BY tmp.Date, tmp.HE ASC;
Zoals in het eerste voorbeeld hier https://www.postgresql.org/docs/8.4/static/queries-with.html