where extract(month FROM birthdate) = extract(month FROM flightdate) and extract(day FROM birthdate) = extract(day FROM flightdate)
order by name;
"""
"""
### 3. Write a query to generate a list: (source_city, source_airport_code, dest_city, dest_airport_code, number_of_flights) for all source-dest pairs with at least 3 flights.
### 3. Write a query to generate a list: (source_city, source_airport_code, dest_city, dest_airport_code, number_of_flights) for all source-dest pairs with at least 3 flights.
### Order first by number_of_flights in decreasing order, then source_city in the increasing order, and then dest_city in the increasing order.
### Order first by number_of_flights in decreasing order, then source_city in the increasing order, and then dest_city in the increasing order.
### Note: You must generate the source and destination cities along with the airport codes.
### Note: You must generate the source and destination cities along with the airport codes.
queries[3]="""
queries[3]="""
with common_flights (flightid, source, dest, airlineid) as (select distinct a.flightid, a.source, a.dest, a.airlineid
select 0;
from flights a, flights b
where (a.source = b.source) and (a.dest = b.dest) and (a.flightid != b.flightid)
order by a.source, a.dest),
common_count (source, dest, count) as
(select source, dest, count(*)
from common_flights
group by source, dest
having count(*) >= 3),
source_city (source_city, source_airport_code, dest_airport_code, number_of_flights) as
(select a.city as source_city, c.*
from common_count c left join airports a
on c.source = a.airportid)
select s.source_city, s.source_airport_code, a.city as dest_city, s.dest_airport_code, s.number_of_flights
from source_city s left join airports a
on s.dest_airport_code = a.airportid
order by number_of_flights desc, source_city, dest_city;
"""
"""
### 4. Find the name of the airline with the maximum number of customers registered as frequent fliers.
### 4. Find the name of the airline with the maximum number of customers registered as frequent fliers.
### Output only the name of the airline. If multiple answers, order by name.
### Output only the name of the airline. If multiple answers, order by name.
queries[4]="""
queries[4]="""
with counts (airlineid, ff_count) as (select frequentflieron, count(frequentflieron) as ff_count
select 0;
from customers
group by frequentflieron
order by frequentflieron),
highest_ff (airlineid, ff_count) as (select airlineid, ff_count
from counts
where ff_count = (select max(ff_count) from counts))
select name
from highest_ff h join airlines a
on h.airlineid = a.airlineid
order by name;
"""
"""
### 5. For all flights from OAK to IAD, list the flight id, airline name, and the
### 5. For all flights from OAK to IAD, list the flight id, airline name, and the
### duration in hours and minutes. So the output will have 4 fields: flightid, airline name,
### duration in hours and minutes. So the output will have 4 fields: flightid, airline name,
### hours, minutes. Order by flightid.
### hours, minutes. Order by flightid.
queries[5]="""
queries[5]="""
with oak_flights (flightid, airlineid, duration) as (select flightid, airlineid, (local_arrival_time - local_departing_time) as duration
select 0;
from flights
where source = 'OAK' and dest = 'IAD')
select flightid, name, extract(hour FROM duration) as hours, extract(minute FROM duration) as minutes
from oak_flights o join airlines a
on o.airlineid = a.airlineid
order by flightid;
"""
"""
### 6. Write a query to find empty flights (flight, flight date) on any date
### 6. Write a query to find empty flights (flight, flight date) on any date
...
@@ -92,20 +48,7 @@ order by flightid;
...
@@ -92,20 +48,7 @@ order by flightid;
### flights took off as scheduled, with or without passengers. Order by flight
### flights took off as scheduled, with or without passengers. Order by flight
### id in increasing order, and then by date in increasing order.
### id in increasing order, and then by date in increasing order.
queries[6]="""
queries[6]="""
with days_of_flights (flight_date) as (select distinct flightdate
select 0;
from flewon),
cart_product (flightid, flight_date) as (select a.flightid, b.flight_date
from flights a, days_of_flights b
order by a.flightid, b.flight_date)
select *
from cart_product
except (select distinct b.flightid, flightdate
from flights a, flewon b
where a.flightid = b.flightid
order by b.flightid, flightdate)
order by flightid, flight_date;
"""
"""
### 7. Write a query to generate a list of customers who don't list Southwest as their frequent flier airline, but
### 7. Write a query to generate a list of customers who don't list Southwest as their frequent flier airline, but
...
@@ -113,27 +56,7 @@ order by flightid, flight_date;
...
@@ -113,27 +56,7 @@ order by flightid, flight_date;
### Output columns: customerid, customer_name
### Output columns: customerid, customer_name
### Order by: customerid
### Order by: customerid
queries[7]="""
queries[7]="""
with counts (customerid, airlineid, frequency) as (select a.customerid, b.airlineid, count(b.airlineid) as frequency
select 0;
from flewon a left join flights b
on a.flightid = b.flightid
group by a.customerid, b.airlineid
order by a.customerid),
maximums (customerid, max) as (select counts.customerid, max(counts.frequency)
from counts
group by counts.customerid
order by counts.customerid),
max_airlines (customerid, airlineid) as (select a.customerid, a.airlineid, b.max
from counts a join maximums b
on a.customerid = b.customerid
where a.frequency = b.max)
select a.customerid, b.name as customer_name
from max_airlines a left join customers b
on a.customerid = b.customerid
where b.frequentflieron != 'SW' and a.airlineid = 'SW'
order by customerid;
"""
"""
### 8. Write a query to generate a list of customers where the interval between first and last flight is 5 days.
### 8. Write a query to generate a list of customers where the interval between first and last flight is 5 days.
...
@@ -141,17 +64,7 @@ order by customerid;
...
@@ -141,17 +64,7 @@ order by customerid;
### Output columns: name
### Output columns: name
### Order by: name
### Order by: name
queries[8]="""
queries[8]="""
with first_last (customerid, interval) as (select customerid, (extract(day FROM max(flightdate)) - extract(day FROM min(flightdate))) as interval
select 0;
from flewon
group by customerid
having extract(month FROM max(flightdate)) = extract(month FROM min(flightdate))
and extract(year FROM max(flightdate)) = extract(year FROM min(flightdate)))
select b.name
from first_last a left join customers b
on a.customerid = b.customerid
where interval = 5
order by b.name;
"""
"""
...
@@ -160,22 +73,7 @@ order by b.name;
...
@@ -160,22 +73,7 @@ order by b.name;
### Output columns: customerid, airlinename
### Output columns: customerid, airlinename
### Order by: customerid, airlinename
### Order by: customerid, airlinename
queries[9]="""
queries[9]="""
with never_flown as ((select customerid, a.airlineid
select 0;
from customers c, airlines a
order by c.customerid)
except
(select a.customerid, b.airlineid
from flewon a left join flights b
on a.flightid = b.flightid
group by a.customerid, b.airlineid
order by a.customerid))
select a.customerid, b.name as airlinename
from never_flown a left join airlines b
on a.airlineid = b.airlineid
order by a.customerid, b.name;
"""
"""
...
@@ -185,13 +83,7 @@ order by a.customerid, b.name;
...
@@ -185,13 +83,7 @@ order by a.customerid, b.name;
### Output columns: name,coupon
### Output columns: name,coupon
### Order by: name,coupon
### Order by: name,coupon
queries[10]="""
queries[10]="""
select name, concat(substring(name, 1, 3),extract(day FROM birthdate)) as coupon
select 0;
from customers a left join flewon b
on a.customerid = b.customerid
where
(extract(month FROM birthdate) = extract(month FROM flightdate)) and
(extract(day FROM birthdate) = extract(day FROM flightdate))
