06_Join.sql

-- The first example shows the goal scored by a player with the last name 'Bender'. The * says to list all the columns in the table - a shorter way of saying matchid, teamid, player, gtime
SELECT matchid, player
FROM goal
WHERE teamid = 'GER'

-- Show id, stadium, team1, team2 for just game 1012
SELECT id, stadium, team1, team2
FROM game
WHERE id = 1012

-- Modify it to show the player, teamid, stadium and mdate for every German goal.
SELECT player, teamid, stadium, mdate
FROM game JOIN goal ON (id=matchid)
WHERE teamid = 'GER'

-- Show the team1, team2 and player for every goal scored by a player called Mario player LIKE 'Mario%'
SELECT team1, team2, player
FROM game JOIN goal ON (id=matchid)
WHERE player LIKE 'Mario%'

-- Show player, teamid, coach, gtime for all goals scored in the first 10 minutes gtime<=10
SELECT player, teamid, coach, gtime
FROM goal JOIN eteam ON teamid=id
WHERE gtime<=10

-- List the dates of the matches and the name of the team in which 'Fernando Santos' was the team1 coach.
SELECT mdate, teamname
FROM game JOIN eteam ON team1 = eteam.id
WHERE coach = 'Fernando Santos'

-- List the player for every goal scored in a game where the stadium was 'National Stadium, Warsaw'
SELECT player
FROM goal JOIN game ON matchid = id
WHERE stadium = 'National Stadium, Warsaw'

-- Instead show the name of all players who scored a goal against Germany.
SELECT DISTINCT player
FROM game JOIN goal ON matchid = id
WHERE teamid != 'GER' AND 'GER' IN (game.team2, game.team1)

-- Show teamname and the total number of goals scored.
SELECT teamname, COUNT(player)
FROM eteam JOIN goal ON id=teamid
GROUP BY teamname

-- Show the stadium and the number of goals scored in each stadium.
SELECT stadium, COUNT(player)
FROM game JOIN goal ON id=matchid
GROUP BY stadium

-- For every match involving 'POL', show the matchid, date and the number of goals scored.
SELECT matchid, mdate, COUNT(player)
FROM game JOIN goal ON matchid = id
WHERE (team1 = 'POL' OR team2 = 'POL')
GROUP BY matchid, mdate;

-- For every match where 'GER' scored, show matchid, match date and the number of goals scored by 'GER'
SELECT matchid, mdate, COUNT(player)
FROM game
    JOIN goal ON id = matchid
WHERE teamid = 'GER' AND 'GER' IN (game.team1, game.team2)
GROUP BY matchid, mdate

-- List every match with the goals scored by each team as shown. This will use "CASE WHEN" which has not been explained in any previous exercises.
SELECT game.mdate,
       game.team1,
       SUM(CASE WHEN goal.teamid = game.team1
                THEN 1
                ELSE 0
           END)
       AS score1,
       game.team2,
       SUM(CASE WHEN goal.teamid = game.team2
                THEN 1
                ELSE 0
           END)
       AS score2
FROM game
LEFT JOIN goal
ON goal.matchid = game.id
GROUP BY game.mdate, game.team1, game.team2
ORDER BY game.mdate