Solution Explanation for Converting Date Format

This problem requires converting dates from a table into a specific string format. The most efficient way to achieve this is by leveraging the built-in date formatting functions provided by the database system (in this case, MySQL).

Approach

The core idea is to use the DATE_FORMAT function in MySQL. This function takes a date value and a format string as input and returns a formatted string representation of the date.

MySQL Solution

The MySQL solution directly utilizes the DATE_FORMAT function. The format string '%W, %M %e, %Y' specifies the desired output format:

• %W: Abbreviated weekday name (e.g., 'Tuesday')
• %M: Full month name (e.g., 'April')
• %e: Day of the month, with a leading space for single-digit days (e.g., '12', ' 9')
• %Y: Year with century (e.g., '2022')

SELECT DATE_FORMAT(day, '%W, %M %e, %Y') AS day FROM Days;

This query selects the day column from the Days table, applies the DATE_FORMAT function to convert each date into the specified format, and assigns the result to a new column named day in the output.

Time Complexity Analysis

The time complexity of this solution is O(N), where N is the number of rows in the Days table. This is because DATE_FORMAT operates on each row individually. The operation is linear with respect to the number of rows; each row takes a constant amount of time to process. The database engine is highly optimized for this type of operation, making it very efficient.

Space Complexity Analysis

The space complexity is O(N) as well, since the output table will contain the same number of rows as the input table. The space used is proportional to the size of the input data. The additional space needed for intermediate calculations within DATE_FORMAT is negligible and considered constant.