SQL Exercise: Find the number of players booked for each team
43. From the following tables, write a SQL query to find out how many players each team has booked. Return country name, number of players booked.
Sample table: soccer_country
country_id | country_abbr | country_name
------------+--------------+---------------------
1201 | ALB | Albania
1202 | AUT | Austria
1203 | BEL | Belgium
1204 | CRO | Croatia
1205 | CZE | Czech Republic
1206 | ENG | England
1207 | FRA | France
1208 | GER | Germany
1209 | HUN | Hungary
1210 | ISL | Iceland
1211 | ITA | Italy
1212 | NIR | Northern Ireland
1213 | POL | Poland
1214 | POR | Portugal
1215 | IRL | Republic of Ireland
1216 | ROU | Romania
1217 | RUS | Russia
1218 | SVK | Slovakia
1219 | ESP | Spain
1220 | SWE | Sweden
1221 | SUI | Switzerland
1222 | TUR | Turkey
1223 | UKR | Ukraine
1224 | WAL | Wales
1225 | SLO | Slovenia
1226 | NED | Netherlands
1227 | SRB | Serbia
1228 | SCO | Scotland
1229 | NOR | Norway
Sample table: player_booked
match_no | team_id | player_id | booking_time | sent_off | play_schedule | play_half
----------+---------+-----------+--------------+----------+---------------+-----------
1 | 1216 | 160349 | 32 | | NT | 1
1 | 1216 | 160355 | 45 | | NT | 1
1 | 1207 | 160159 | 69 | Y | NT | 2
1 | 1216 | 160360 | 78 | | NT | 2
2 | 1221 | 160470 | 14 | | NT | 1
2 | 1201 | 160013 | 23 | | NT | 1
2 | 1201 | 160013 | 36 | | NT | 1
2 | 1201 | 160014 | 63 | | NT | 2
2 | 1221 | 160472 | 66 | | NT | 2
2 | 1201 | 160015 | 89 | | NT | 2
2 | 1201 | 160009 | 93 | | NT | 2
3 | 1218 | 160401 | 2 | | ST | 2
3 | 1218 | 160406 | 31 | | NT | 1
3 | 1218 | 160408 | 78 | | NT | 2
3 | 1218 | 160411 | 80 | | NT | 2
3 | 1218 | 160407 | 83 | | NT | 2
4 | 1206 | 160120 | 62 | | NT | 2
4 | 1217 | 160377 | 72 | | NT | 2
5 | 1222 | 160505 | 31 | | NT | 1
5 | 1222 | 160490 | 48 | | NT | 2
5 | 1204 | 160077 | 80 | | NT | 2
5 | 1222 | 160502 | 91 | | NT | 2
6 | 1213 | 160290 | 65 | | NT | 2
6 | 1212 | 160258 | 69 | | NT | 2
6 | 1213 | 160284 | 89 | | NT | 2
7 | 1223 | 160518 | 68 | | NT | 2
8 | 1205 | 160100 | 61 | | NT | 2
9 | 1215 | 160336 | 43 | | NT | 1
9 | 1220 | 160445 | 61 | | NT | 2
9 | 1215 | 160341 | 77 | | NT | 2
10 | 1211 | 160236 | 65 | | NT | 2
10 | 1211 | 160248 | 75 | | NT | 2
10 | 1211 | 160235 | 78 | | NT | 2
10 | 1211 | 160245 | 84 | | NT | 2
10 | 1203 | 160057 | 93 | | NT | 2
11 | 1202 | 160027 | 33 | | NT | 1
11 | 1202 | 160027 | 66 | Y | NT | 2
11 | 1209 | 160204 | 80 | | NT | 2
12 | 1210 | 160227 | 2 | | ST | 2
12 | 1210 | 160221 | 55 | | NT | 2
13 | 1218 | 160395 | 46 | | NT | 2
14 | 1221 | 160480 | 2 | | ST | 2
14 | 1216 | 160361 | 22 | | NT | 1
14 | 1216 | 160357 | 24 | | NT | 1
14 | 1216 | 160367 | 37 | | NT | 1
14 | 1221 | 160477 | 50 | | NT | 2
14 | 1216 | 160352 | 76 | | NT | 2
15 | 1201 | 160015 | 55 | | NT | 2
15 | 1201 | 160011 | 81 | | NT | 2
15 | 1207 | 160152 | 88 | | NT | 2
16 | 1224 | 160535 | 61 | | NT | 2
17 | 1223 | 160528 | 40 | | NT | 1
17 | 1212 | 160272 | 63 | | NT | 2
17 | 1223 | 160523 | 67 | | NT | 2
17 | 1212 | 160266 | 87 | | NT | 2
17 | 1212 | 160259 | 90 | | NT | 2
18 | 1208 | 160175 | 3 | | NT | 1
18 | 1213 | 160294 | 3 | | ST | 2
18 | 1208 | 160177 | 34 | | NT | 1
18 | 1213 | 160293 | 45 | | NT | 1
18 | 1213 | 160288 | 55 | | NT | 2
18 | 1208 | 160165 | 67 | | NT | 2
19 | 1211 | 160242 | 69 | | NT | 2
19 | 1220 | 160447 | 89 | | NT | 2
19 | 1211 | 160231 | 94 | | NT | 2
20 | 1204 | 160080 | 14 | | NT | 1
20 | 1205 | 160101 | 72 | | NT | 2
20 | 1204 | 160081 | 74 | | NT | 2
20 | 1204 | 160078 | 88 | | NT | 2
21 | 1219 | 160424 | 2 | | NT | 1
21 | 1222 | 160504 | 9 | | NT | 1
21 | 1222 | 160500 | 41 | | NT | 1
22 | 1215 | 160334 | 42 | | NT | 1
22 | 1203 | 160056 | 49 | | NT | 2
23 | 1209 | 160199 | 2 | | ST | 2
23 | 1210 | 160229 | 42 | | NT | 1
23 | 1210 | 160227 | 75 | | NT | 2
23 | 1210 | 160216 | 77 | | NT | 2
23 | 1209 | 160192 | 81 | | NT | 2
23 | 1209 | 160197 | 83 | | NT | 2
24 | 1202 | 160028 | 6 | | NT | 1
24 | 1214 | 160321 | 31 | | NT | 1
24 | 1214 | 160307 | 40 | | NT | 1
24 | 1202 | 160037 | 47 | | NT | 2
24 | 1202 | 160029 | 78 | | NT | 2
24 | 1202 | 160042 | 86 | | NT | 2
25 | 1201 | 160012 | 6 | | NT | 1
25 | 1216 | 160353 | 54 | | NT | 2
25 | 1201 | 160017 | 85 | | NT | 2
25 | 1216 | 160356 | 85 | | NT | 2
25 | 1216 | 160364 | 91 | | NT | 2
25 | 1201 | 160007 | 95 | | NT | 2
26 | 1207 | 160147 | 25 | | NT | 1
26 | 1207 | 160145 | 83 | | NT | 2
27 | 1224 | 160551 | 16 | | NT | 1
27 | 1217 | 160383 | 64 | | NT | 2
28 | 1218 | 160409 | 24 | | NT | 1
28 | 1206 | 160119 | 52 | | NT | 2
29 | 1223 | 160520 | 25 | | NT | 1
29 | 1223 | 160513 | 38 | | NT | 1
29 | 1213 | 160290 | 60 | | NT | 2
31 | 1222 | 160491 | 35 | | NT | 1
31 | 1205 | 160108 | 36 | | NT | 1
31 | 1205 | 160107 | 39 | Y | NT | 1
31 | 1222 | 160490 | 50 | | NT | 2
31 | 1205 | 160112 | 87 | | NT | 2
32 | 1204 | 160087 | 29 | | NT | 1
32 | 1204 | 160079 | 70 | | NT | 2
32 | 1204 | 160076 | 70 | | NT | 2
32 | 1204 | 160085 | 88 | | NT | 2
33 | 1210 | 160218 | 36 | | NT | 1
33 | 1210 | 160230 | 51 | | NT | 2
33 | 1202 | 160045 | 70 | | NT | 2
33 | 1210 | 160220 | 78 | | NT | 2
33 | 1210 | 160208 | 82 | | NT | 2
34 | 1209 | 160190 | 13 | | NT | 1
34 | 1209 | 160191 | 28 | | NT | 1
34 | 1209 | 160203 | 34 | | NT | 1
34 | 1209 | 160202 | 56 | | NT | 2
35 | 1211 | 160233 | 39 | | NT | 1
35 | 1215 | 160343 | 39 | | NT | 1
35 | 1215 | 160332 | 73 | | NT | 2
35 | 1211 | 160234 | 78 | | NT | 2
35 | 1211 | 160253 | 87 | | NT | 2
35 | 1211 | 160251 | 93 | | NT | 2
36 | 1203 | 160064 | 1 | | ST | 1
36 | 1203 | 160055 | 30 | | NT | 1
36 | 1220 | 160451 | 72 | | NT | 2
37 | 1221 | 160470 | 55 | | NT | 2
37 | 1213 | 160282 | 58 | | NT | 2
38 | 1212 | 160266 | 44 | | NT | 1
38 | 1224 | 160538 | 58 | | NT | 2
38 | 1212 | 160267 | 67 | | NT | 2
38 | 1224 | 160544 | 92 | | NT | 2
39 | 1214 | 160318 | 78 | | NT | 2
40 | 1215 | 160328 | 25 | | NT | 1
40 | 1207 | 160152 | 27 | | NT | 1
40 | 1215 | 160334 | 41 | | NT | 1
40 | 1207 | 160147 | 44 | | NT | 1
40 | 1215 | 160329 | 66 | Y | NT | 2
40 | 1215 | 160343 | 72 | | NT | 2
41 | 1218 | 160407 | 2 | | ST | 2
41 | 1218 | 160401 | 13 | | NT | 1
41 | 1208 | 160169 | 46 | | NT | 2
41 | 1208 | 160168 | 67 | | NT | 2
42 | 1209 | 160192 | 34 | | NT | 1
42 | 1209 | 160194 | 47 | | NT | 2
42 | 1209 | 160196 | 61 | | NT | 2
42 | 1203 | 160056 | 67 | | NT | 2
42 | 1203 | 160065 | 89 | | NT | 2
42 | 1203 | 160061 | 91 | | NT | 2
42 | 1209 | 160207 | 92 | | NT | 2
43 | 1219 | 160431 | 2 | | ST | 2
43 | 1211 | 160238 | 24 | | NT | 1
43 | 1219 | 160436 | 41 | | NT | 1
43 | 1211 | 160252 | 54 | | NT | 2
43 | 1211 | 160245 | 89 | | NT | 2
43 | 1219 | 160427 | 89 | | NT | 2
43 | 1219 | 160421 | 89 | | NT | 2
44 | 1210 | 160208 | 38 | | NT | 1
44 | 1206 | 160137 | 47 | | NT | 2
44 | 1210 | 160222 | 65 | | NT | 2
45 | 1214 | 160318 | 2 | | ST | 2
45 | 1213 | 160282 | 42 | | NT | 1
45 | 1213 | 160281 | 66 | | NT | 2
45 | 1214 | 160310 | 70 | | NT | 2
45 | 1213 | 160290 | 89 | | NT | 2
46 | 1224 | 160535 | 5 | | NT | 1
46 | 1224 | 160533 | 16 | | NT | 1
46 | 1224 | 160536 | 24 | | NT | 1
46 | 1203 | 160061 | 59 | | NT | 2
46 | 1224 | 160544 | 75 | | NT | 2
46 | 1203 | 160050 | 85 | | NT | 2
47 | 1211 | 160247 | 56 | | NT | 2
47 | 1211 | 160238 | 57 | | NT | 2
47 | 1211 | 160246 | 59 | | NT | 2
47 | 1208 | 160168 | 90 | | NT | 2
47 | 1208 | 160180 | 112 | | NT | 2
48 | 1210 | 160221 | 58 | | NT | 2
48 | 1207 | 160149 | 75 | | NT | 2
49 | 1224 | 160540 | 8 | | NT | 1
49 | 1224 | 160533 | 62 | | NT | 2
49 | 1214 | 160303 | 71 | | NT | 2
49 | 1214 | 160322 | 72 | | NT | 2
49 | 1224 | 160547 | 88 | | NT | 2
50 | 1208 | 160177 | 1 | | ST | 1
50 | 1208 | 160172 | 36 | | NT | 1
50 | 1207 | 160143 | 43 | | NT | 1
50 | 1208 | 160180 | 45 | | NT | 1
50 | 1208 | 160173 | 50 | | NT | 2
50 | 1207 | 160152 | 75 | | NT | 2
51 | 1214 | 160304 | 34 | | NT | 1
51 | 1214 | 160313 | 62 | | NT | 2
51 | 1207 | 160149 | 80 | | NT | 2
51 | 1214 | 160308 | 95 | | ET | 1
51 | 1207 | 160153 | 97 | | ET | 1
51 | 1214 | 160318 | 98 | | ET | 1
51 | 1207 | 160145 | 107 | | ET | 2
51 | 1207 | 160155 | 115 | | ET | 2
51 | 1214 | 160306 | 119 | | ET | 2
51 | 1214 | 160302 | 122 | | ET | 2
Sample Solution:
SQL Code:
-- Selecting the country name from the soccer_country table and counting the number of bookings for each country
SELECT
a.country_name, -- Selecting the country name from the soccer_country table aliased as 'a'
COUNT(b.*) AS Booked -- Counting the number of bookings for each country
FROM
soccer_country a -- Specifying the soccer_country table with an alias 'a'
JOIN
player_booked b ON a.country_id = b.team_id -- Joining the soccer_country table with the player_booked table based on the country_id
GROUP BY
a.country_name -- Grouping the results by country name
-- Ordering the results by the count of bookings in descending order
ORDER BY
Booked DESC;
Sample Output:
country_name | booked
---------------------+--------
Italy | 16
France | 13
Portugal | 13
Iceland | 12
Hungary | 12
Germany | 11
Wales | 11
Romania | 10
Poland | 10
Albania | 10
Belgium | 9
Slovakia | 9
Republic of Ireland | 9
Croatia | 8
Austria | 7
Turkey | 7
Northern Ireland | 6
Ukraine | 5
Czech Republic | 5
Spain | 5
Switzerland | 5
England | 3
Sweden | 3
Russia | 2
(24 rows)
Code Explanation:
The said query in SQL that selects the country name and counts the number of bookings for each country from the tables 'soccer_country' and 'player_booked'.
The JOIN clause joins the 'soccer_country' table aliased as "a" with the 'player_booked' table aliased as "b" using the country ID from "a" and the team ID from "b".
It then groups the results by country name and orders them in descending order based on the number of bookings so that the country with the most bookings appears first.
Alternative Solutions:
Using a Subquery in the FROM Clause:
-- Selecting the country name and the count of bookings from the soccer_country table and a subquery
SELECT
a.country_name, -- Selecting the country name from the soccer_country table aliased as 'a'
b.Booked -- Selecting the count of bookings from the subquery aliased as 'b'
FROM
soccer_country a -- Specifying the soccer_country table with an alias 'a'
JOIN
( -- Subquery to count bookings for each team
SELECT
team_id, -- Selecting the team_id from the player_booked table
COUNT(*) AS Booked -- Counting the number of bookings for each team
FROM
player_booked -- Specifying the player_booked table
GROUP BY
team_id -- Grouping the bookings by team_id
) b ON a.country_id = b.team_id -- Joining the soccer_country table with the subquery based on country_id
WHERE
b.Booked > 0 -- Filtering out teams with no bookings
-- Ordering the results by the count of bookings in descending order
ORDER BY
b.Booked DESC;
Explanation:
This query uses a subquery in the FROM clause to calculate the count of booked instances for each country. It then performs a LEFT JOIN with the soccer_country table to ensure all countries are included in the results, even if they have no bookings. The results are ordered by Booked in descending order.
Using a Correlated Subquery:
-- Selecting the country name and the count of bookings from the soccer_country table with a subquery
SELECT
a.country_name, -- Selecting the country name from the soccer_country table aliased as 'a'
( -- Subquery to count bookings for each country
SELECT
COUNT(*) -- Counting the number of bookings for each team in the player_booked table
FROM
player_booked b -- Specifying the player_booked table with an alias 'b'
WHERE
a.country_id = b.team_id -- Matching the team_id from the outer query with the team_id in the subquery
) AS Booked -- Aliasing the count of bookings as 'Booked'
FROM
soccer_country a -- Specifying the soccer_country table with an alias 'a'
WHERE
( -- Subquery to filter out countries with no bookings
SELECT
COUNT(*) -- Counting the number of bookings for each team in the player_booked table
FROM
player_booked b -- Specifying the player_booked table with an alias 'b'
WHERE
a.country_id = b.team_id -- Matching the team_id from the outer query with the team_id in the subquery
) > 0 -- Filtering out countries with no bookings
-- Ordering the results by the count of bookings in descending order
ORDER BY
Booked DESC;
Explanation:
This query uses a correlated subquery to calculate the count of booked instances for each country. The subquery counts the bookings for each team, correlated to the outer query's country_id. The results are ordered by Booked in descending order.
Practice Online
Sample Database: soccer
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