Untitled

#1
SELECT DATE
FROM Observation
WHERE PRCP>0
ORDER BY date asc LIMIT 1 ;

#2
SELECT s.name AS station
FROM Station AS s,Observation AS o
WHERE PRCP>0 AND s.id = o.station
ORDER BY date ASC LIMIT 1 ;

#3
SELECT c.name AS country, COUNT(*) AS count
FROM Station AS s, Country AS p, Continent AS c
WHERE s.country = p.fips AND p.continent = c.cc
GROUP BY c.name;

#4
SELECT
   YEAR(date) AS year,
   AVG(TMAX) AS avg_max_temp
FROM Observation AS o, Station AS s
WHERE o.station = s.id AND s.country = 'PO'
GROUP BY YEAR(date)
ORDER BY YEAR(date) ASC;

#5
SELECT
   MONTH(date) AS month,
   AVG(PRCP) AS precipitation,
   MAX(TMAX) AS max_temp,
   MIN(TMIN) AS min_temp,
   MAX(TMAX) - MIN(TMIN) AS temp_amplitude
FROM Observation AS o, Station AS s
WHERE o.date >= 2013-01-01 AND o.station = s.id AND s.country = 'UK'
GROUP BY MONTH(date)
ORDER BY MONTH ASC;

#6 - nao sei se vale a pena printar isto tudo
SELECT
   AVG(CASE WHEN YEAR(date) = 2006 THEN PRCP END) AS avg_precip_2006,
   MAX(CASE WHEN YEAR(date) = 2006 THEN TMAX END) AS max_temp_2006,
   MIN(CASE WHEN YEAR(date) = 2006 THEN TMIN END) AS min_temp_2006,
   AVG(CASE WHEN YEAR(date) = 2021 THEN PRCP END) AS avg_precip_2021,
   MAX(CASE WHEN YEAR(date) = 2021 THEN TMAX END) AS max_temp_2021,
   MIN(CASE WHEN YEAR(date) = 2021 THEN TMIN END) AS min_temp_2021,
   AVG(CASE WHEN YEAR(date) = 2021 THEN PRCP END)
     - AVG(CASE WHEN YEAR(date) = 2006 THEN PRCP END) AS diff_avg_precip,
   MAX(CASE WHEN YEAR(date) = 2021 THEN TMAX END)
     - MAX(CASE WHEN YEAR(date) = 2006 THEN TMAX END) AS diff_max_temp,
   MIN(CASE WHEN YEAR(date) = 2021 THEN TMIN END)
     - MIN(CASE WHEN YEAR(date) = 2006 THEN TMIN END) AS diff_min_temp
FROM Observation AS o, Station AS s
WHERE YEAR(date) IN (2006,2021) AND o.station = s.id AND s.country = 'UK';