SQL Exercise: Referee who assisted in the opening match

SQL soccer Database: Joins Exercise-10 with Solution

10. From the following tables, write a SQL query to find the referee who assisted the referee in the opening match. Return associated referee name, country name.

Sample table: asst_referee_mast

Sample table: soccer_country

Sample table: match_details

Sample Solution:

SQL Code:

SELECT ass_ref_name, country_name 
FROM asst_referee_mast a
JOIN soccer_country b
ON a.country_id=b.country_id
JOIN match_details c
ON a.ass_ref_id=c.ass_ref
WHERE match_no=1;

Sample Output:

 ass_ref_name | country_name
--------------+--------------
 Gyorgy Ring  | Hungary
 Vencel Toth  | Hungary
(2 rows)

Code Explanation:

The said query in SQL that retrieves information about the assistant referee and country for the match with match_no equal to 1 from the tables asst_referee_mast, soccer_country, and match_details.
The JOIN keyword is used to join the tables based on columns specified in the ON clause. The asst_referee_mast and soccer_country are joined on the country_id column, while asst_referee_mast and match_details are joined on the ass_ref_id column.
The condition filters only those rows for the match with match_no equal to 1 will be selected.

Relational Algebra Expression:

Relational Algebra Tree:

Practice Online

Sample Database: soccer

Query Visualization:

Duration:

Rows:

Cost:

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