SQL Exercise: Find the players who booked most number of times

SQL soccer Database: Joins Exercise-42 with Solution

42. From the following tables, write a SQL query to count the players who booked the most number of times. Return player name, number of players who booked most number of times.

Sample table: soccer_country

Sample table: player_booked

Sample table: player_mast

Sample Solution:

SQL Code:

SELECT c.player_name,COUNT(b.*) Booked 
FROM soccer_country a
JOIN player_booked b ON a.country_id=b.team_id
JOIN player_mast c ON b.player_id=c.player_id
GROUP BY c.player_name
having COUNT(b.*)=(
SELECT MAX(mm) FROM (
SELECT COUNT(*) mm 
FROM player_booked 
GROUP BY player_id) inner_result);

Sample Output:

    player_name    | booked
-------------------+--------
 NGolo Kante       |      3
 William Carvalho  |      3
 Bartosz Kapustka  |      3
(3 rows)

Code Explanation:

The said query in SQL that joins three tables soccer_country, player_booked, and player_mast and groups the results by player name.
The JOIN clause joins the soccer_country and player_booked tables based on the country_id and team_id columns, and joins the result set with the table player_mast based on the player_id column.
Groups the results by player_name, so that the query can aggregate bookings by player.
Using a subquery finds the player with the highest number of bookings, and returns only that player's name and the number of bookings they have. The subquery first counts the number of bookings per player in the player_booked table, groups the result by player_id, and selects the maximum count. The outer query then filters the results to only include the player with that maximum count.

Practice Online

Sample Database: soccer

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous SQL Exercise: Players with their teams booked in the tournament.
Next SQL Exercise: Find the number of players booked for each team.