SQL Exercise: Find the venue with number of goals that has seen
18. From the following tables, write a SQL query to count the number of goals that have been seen. Return venue name and number of goals.
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
........
1229 | NOR | Norway
Sample table: goal_details
goal_id | match_no | player_id | team_id | goal_time | goal_type | play_stage | goal_schedule | goal_half
---------+----------+-----------+---------+-----------+-----------+------------+---------------+-----------
1 | 1 | 160159 | 1207 | 57 | N | G | NT | 2
2 | 1 | 160368 | 1216 | 65 | P | G | NT | 2
3 | 1 | 160154 | 1207 | 89 | N | G | NT | 2
4 | 2 | 160470 | 1221 | 5 | N | G | NT | 1
5 | 3 | 160547 | 1224 | 10 | N | G | NT | 1
6 | 3 | 160403 | 1218 | 61 | N | G | NT | 2
7 | 3 | 160550 | 1224 | 81 | N | G | NT | 2
8 | 4 | 160128 | 1206 | 73 | N | G | NT | 2
9 | 4 | 160373 | 1217 | 93 | N | G | ST | 2
........
108 | 51 | 160319 | 1214 | 109 | N | F | ET | 2
Sample table: match_mast
match_no | play_stage | play_date | results | decided_by | goal_score | venue_id | referee_id | audence | plr_of_match | stop1_sec | stop2_sec
----------+------------+------------+---------+------------+------------+----------+------------+---------+--------------+-----------+-----------
1 | G | 2016-06-11 | WIN | N | 2-1 | 20008 | 70007 | 75113 | 160154 | 131 | 242
2 | G | 2016-06-11 | WIN | N | 0-1 | 20002 | 70012 | 33805 | 160476 | 61 | 182
3 | G | 2016-06-11 | WIN | N | 2-1 | 20001 | 70017 | 37831 | 160540 | 64 | 268
4 | G | 2016-06-12 | DRAW | N | 1-1 | 20005 | 70011 | 62343 | 160128 | 0 | 185
5 | G | 2016-06-12 | WIN | N | 0-1 | 20007 | 70006 | 43842 | 160084 | 125 | 325
6 | G | 2016-06-12 | WIN | N | 1-0 | 20006 | 70014 | 33742 | 160291 | 2 | 246
7 | G | 2016-06-13 | WIN | N | 2-0 | 20003 | 70002 | 43035 | 160176 | 89 | 188
8 | G | 2016-06-13 | WIN | N | 1-0 | 20010 | 70009 | 29400 | 160429 | 360 | 182
9 | G | 2016-06-13 | DRAW | N | 1-1 | 20008 | 70010 | 73419 | 160335 | 67 | 194
.........
51 | F | 2016-07-11 | WIN | N | 1-0 | 20008 | 70005 | 75868 | 160307 | 161 | 181
Sample table:soccer_venue
venue_id | venue_name | city_id | aud_capacity
----------+-------------------------+---------+--------------
20001 | Stade de Bordeaux | 10003 | 42115
20002 | Stade Bollaert-Delelis | 10004 | 38223
20003 | Stade Pierre Mauroy | 10005 | 49822
20004 | Stade de Lyon | 10006 | 58585
20005 | Stade VElodrome | 10007 | 64354
20006 | Stade de Nice | 10008 | 35624
20007 | Parc des Princes | 10001 | 47294
20008 | Stade de France | 10002 | 80100
20009 | Stade Geoffroy Guichard | 10009 | 42000
20010 | Stadium de Toulouse | 10010 | 33150
Sample Solution:
SQL Code:
-- Selecting venue_name and the count of goals scored in each venue
SELECT venue_name, count(venue_name)
-- From clause with JOINs between goal_details, soccer_country, match_mast, and soccer_venue
FROM goal_details
JOIN soccer_country ON goal_details.team_id = soccer_country.country_id
JOIN match_mast ON goal_details.match_no = match_mast.match_no
JOIN soccer_venue ON match_mast.venue_id = soccer_venue.venue_id
-- Grouping the results by venue_name to count goals scored in each venue
GROUP BY venue_name
-- Ordering the results by the count of goals scored in each venue in descending order
ORDER BY COUNT(venue_name) DESC;
Sample Output:
venue_name | count
-------------------------+-------
Stade de France | 18
Stade de Lyon | 16
Stade Pierre Mauroy | 13
Stade de Bordeaux | 13
Stade VElodrome | 11
Stadium de Toulouse | 9
Stade de Nice | 8
Stade Geoffroy Guichard | 8
Stade Bollaert-Delelis | 7
Parc des Princes | 5
(10 rows)
Code Explanation:
The said query in SQL that selects a list of all venues along with the count of goals scored at each venue from the tables 'goal_details', 'soccer_country', 'match_mast', and 'soccer_venue'.
Using multiple JOIN operations the 'goal_details' and 'soccer_country' tables are joined based on the team ID and country ID columns, the 'goal_details' and 'match_mast' tables are joined based on the match number column,
the 'match_mast' and 'soccer_venue' tables are joined based on the venue ID column.
The GROUP BY clause groups the results by venue name. This means that the COUNT(venue_name) function will count the number of goals scored at each venue.
The ORDER BY clause sorts the results in descending order based on the count of goals scored at each venue. The venues with the most goals scored will be listed first.
Alternative Solutions:
Subquery with EXISTS:
-- Selecting venue_name and the count of goals scored in each venue
SELECT v.venue_name, COUNT(gd.goal_id) as num_goals
-- From clause with JOINs between soccer_venue, match_mast, and goal_details
FROM soccer_venue v
JOIN match_mast m ON v.venue_id = m.venue_id
JOIN goal_details gd ON m.match_no = gd.match_no
-- Where clause with EXISTS subquery to filter results for matches with at least one goal
WHERE EXISTS (
-- Subquery to check if there is at least one goal_details record for the match
SELECT 1
FROM goal_details gd2
WHERE gd2.match_no = gd.match_no
)
-- Grouping the results by venue_name to count goals scored in each venue
GROUP BY v.venue_name
-- Ordering the results by the count of goals scored in each venue in descending order
ORDER BY num_goals DESC;
Explanation:
This query uses an EXISTS subquery to check if there's at least one record in goal_details for each match. It joins soccer_venue, match_mast, and goal_details, and then uses the EXISTS clause to filter the results.
Using Inner Join with Goal_Details:
-- Selecting venue_name and the count of goals scored in each venue
SELECT v.venue_name, COUNT(gd.goal_id) as num_goals
-- From clause with JOINs between soccer_venue, match_mast, and goal_details
FROM soccer_venue v
JOIN match_mast m ON v.venue_id = m.venue_id
JOIN goal_details gd ON m.match_no = gd.match_no
-- Grouping the results by venue_name to count goals scored in each venue
GROUP BY v.venue_name
-- Ordering the results by the count of goals scored in each venue in descending order
ORDER BY num_goals DESC;
Explanation:
This query directly joins all the necessary tables (soccer_venue, match_mast, goal_details, and soccer_country) using inner joins and then counts the goals.
Using a Subquery in the WHERE Clause:
-- Selecting venue_name and the count of goals scored in each venue
SELECT v.venue_name, COUNT(gd.goal_id) as num_goals
-- From clause with JOINs between soccer_venue, match_mast, and goal_details
FROM soccer_venue v
JOIN match_mast m ON v.venue_id = m.venue_id
JOIN goal_details gd ON m.match_no = gd.match_no
-- Where clause to filter results for matches that have at least one goal
WHERE m.match_no IN (
-- Subquery to select distinct match_no values with at least one goal_details record
SELECT DISTINCT gd2.match_no
FROM goal_details gd2
)
-- Grouping the results by venue_name to count goals scored in each venue
GROUP BY v.venue_name
-- Ordering the results by the count of goals scored in each venue in descending order
ORDER BY num_goals DESC;
Explanation:
This query uses a subquery in the WHERE clause to filter the matches. It first selects distinct match numbers from goal_details and then checks if the match number is in the list of matches for each venue. This way, only venues with at least one goal are included in the result.
Relational Algebra Expression:
Relational Algebra Tree:
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Practice Online
Sample Database: soccer
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