Final answer:
The subject of this question is Computers and Technology. The query combines data from two tables using the JOIN clause and retrieves only unique names.
Step-by-step explanation:
The subject of this question is Computers and Technology. The query that is being executed is a SQL query using the JOIN clause to combine data from two tables, Person and Oscar, based on a common column, person_id. The SELECT DISTINCT statement is used to retrieve only unique values of the name column from the Person table.
The provided SQL query selects distinct names from the "Person" table (aliased as "P") where there is a match with the "Oscar" table based on the "person_id" column. The "JOIN" keyword is used to combine rows from both tables where the "person_id" values match.
The query returns a list of distinct names from the "Person" table for individuals who have corresponding entries in the "Oscar" table based on matching "person_id" values.