Solution Explanation

This problem requires querying two tables, TVProgram and Content, to find the titles of kid-friendly movies streamed in June 2020. The solution uses SQL to achieve this.

Approach

The core idea is to perform a join operation between the two tables based on content_id, followed by filtering based on the required conditions:

1. Join: An INNER JOIN (or implicitly using JOIN in some SQL dialects like MySQL) is used to combine rows from TVProgram and Content where the content_id matches. This combines the program information with the content details.

2. Filter program_date: The WHERE clause filters the results to include only entries where the program_date falls within June 2020. The specific method for date filtering might vary slightly depending on the SQL dialect (e.g., DATE_FORMAT in MySQL).

3. Filter Kids_content and content_type: The WHERE clause further filters for rows where Kids_content is 'Y' (kid-friendly) and content_type is 'Movies'.

4. Select title and remove duplicates: SELECT DISTINCT title ensures that only unique movie titles are returned.

Time Complexity Analysis

The time complexity is dominated by the join operation. In the worst case, if there are m rows in TVProgram and n rows in Content, the join operation could take O(m*n) time in a naive implementation (nested loops join). However, most database systems use optimized join algorithms (like hash joins or merge joins) that significantly improve performance in practice. The filtering steps have a linear time complexity, O(k), where k is the number of rows after the join. Therefore, the overall time complexity is largely determined by the database's join optimization, but it's bounded by the size of the joined data, making it practically efficient for reasonably sized tables.

Space Complexity Analysis

The space complexity is primarily determined by the intermediate result set generated after the join operation. In the worst case, this could be O(m*n) but usually less due to filtering. The final output (the set of unique titles) will occupy space proportional to the number of distinct titles, which is generally much smaller than the size of the input tables.

Code in MySQL

SELECT DISTINCT title
FROM
    TVProgram
    JOIN Content USING (content_id)
WHERE
    DATE_FORMAT(program_date, '%Y%m') = '202006'
    AND kids_content = 'Y'
    AND content_type = 'Movies';
 

This MySQL query directly implements the approach described above. It uses DATE_FORMAT to extract the year and month from program_date for efficient filtering. The USING (content_id) clause is a shorthand for joining based on the common column.

This detailed explanation provides a comprehensive understanding of the solution, including the approach, algorithm, time and space complexity, and the SQL code implementation.