1783. Grand Slam Titles π
Description
Table: Players
+----------------+---------+ | Column Name | Type | +----------------+---------+ | player_id | int | | player_name | varchar | +----------------+---------+ player_id is the primary key (column with unique values) for this table. Each row in this table contains the name and the ID of a tennis player.
Table: Championships
+---------------+---------+ | Column Name | Type | +---------------+---------+ | year | int | | Wimbledon | int | | Fr_open | int | | US_open | int | | Au_open | int | +---------------+---------+ year is the primary key (column with unique values) for this table. Each row of this table contains the IDs of the players who won one each tennis tournament of the grand slam.
Write a solution to report the number of grand slam tournaments won by each player. Do not include the players who did not win any tournament.
Return the result table in any order.
The result format is in the following example.
Example 1:
Input: Players table: +-----------+-------------+ | player_id | player_name | +-----------+-------------+ | 1 | Nadal | | 2 | Federer | | 3 | Novak | +-----------+-------------+ Championships table: +------+-----------+---------+---------+---------+ | year | Wimbledon | Fr_open | US_open | Au_open | +------+-----------+---------+---------+---------+ | 2018 | 1 | 1 | 1 | 1 | | 2019 | 1 | 1 | 2 | 2 | | 2020 | 2 | 1 | 2 | 2 | +------+-----------+---------+---------+---------+ Output: +-----------+-------------+-------------------+ | player_id | player_name | grand_slams_count | +-----------+-------------+-------------------+ | 2 | Federer | 5 | | 1 | Nadal | 7 | +-----------+-------------+-------------------+ Explanation: Player 1 (Nadal) won 7 titles: Wimbledon (2018, 2019), Fr_open (2018, 2019, 2020), US_open (2018), and Au_open (2018). Player 2 (Federer) won 5 titles: Wimbledon (2020), US_open (2019, 2020), and Au_open (2019, 2020). Player 3 (Novak) did not win anything, we did not include them in the result table.
Solutions
Solution 1: Union All + Equi-Join + Group By
We can use UNION ALL
to merge all player IDs who won Grand Slam titles into a table T
, then use an equi-join JOIN
to join T
table with Players
table on player_id
, and finally use GROUP BY
and COUNT
to count the number of Grand Slam titles won by each player.
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Solution 2
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