The nobel table can be used to practice more SUM and COUNT functions.
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Nobel Prizes: Aggregate functions
This tutorial concerns aggregate functions such as COUNT,
SUM and AVG.
Exercises
Using MAX, AVG, DISTINCT and ORDER BY
How many prizes
Show the total number of prizes awarded.
SELECT COUNT(winner) FROM nobel
SELECT COUNT(winner) FROM nobel
Subjects
List each subject - just once
SELECT DISTINCT subject FROM nobel
How many physics prizes
Show the total number of prizes awarded for Physics.
nobel(yr, subject, winner)
SELECT COUNT(subject) FROM nobel
WHERE subject='Physics'
Number of prizes for each subject
Using GROUP BY and HAVING.
For each subject show the subject and the number of prizes.
nobel(yr,subject, winner)
SELECT subject, COUNT(winner)
FROM nobel
GROUP BY subject
Inaugural prizes
For each subject show the first year that the prize was awarded.
nobel(yr, subject, winner)
SELECT subject, MIN(yr)
FROM nobel
GROUP BY subject
Millenial prizes
For each subject show the number of prizes awarded in the year 2000.
nobel(yr, subject, winner)
SELECT subject,COUNT(yr)
FROM nobel
WHERE yr=2000
GROUP BY subject
Number of winners by subject
Look into aggregates with DISTINCT.
Show the number of different winners for each subject. Be aware that Frederick Sanger has won the chemistry prize twice - he should only be counted once.
nobel(yr, subject, winner)
SELECT subject,COUNT(DISTINCT winner)
FROM nobel
GROUP BY subject
Number of years for each subject
For each subject show how many years have had prizes awarded.
nobel(yr, subject, winner)
SELECT subject,COUNT(DISTINCT yr)
FROM nobel
GROUP BY subject
Triple physics
Using HAVING.
Show the years in which three prizes were given for Physics.
nobel(yr, subject, winner)
SELECT yr
FROM nobel
WHERE subject='Physics'
GROUP BY yr
HAVING COUNT(winner)=3
Who won twice
Show winners who have won more than once.
nobel(yr, subject, winner)
SELECT winner
FROM nobel
GROUP BY winner
HAVING COUNT(yr) > 1
Polymaths
Show winners who have won more than one subject.
nobel(yr, subject, winner)
SELECT winner
FROM nobel
GROUP BY winner
HAVING COUNT(DISTINCT subject)>1
Triples
GROUP BY yr, subject
Show the year and subject where 3 prizes were given. Show only years 2000 onwards.
nobel(yr, subject, winner)
SELECT yr,subject
FROM nobel
WHERE yr>=2000
GROUP BY yr,subject
HAVING COUNT(winner)=3
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