It seems you have a MySQL database with two tables: users and feeds. The users table has a field called screenname, and the feeds table has a field called whoFirstSubscribed, which stores the value of the screenname from the users table.

Based on this information, I assume you have a one-to-many relationship between the users and feeds tables, where one user can be the first subscriber for many feeds.

Here's a simple example of how these tables might be structured:

users table

feeds table

To create these tables, you could use the following SQL statements:

sql
CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    screenname VARCHAR(255) NOT NULL UNIQUE,
    -- Add other fields as needed
);

CREATE TABLE feeds (
    id INT AUTO_INCREMENT PRIMARY KEY,
    whoFirstSubscribed VARCHAR(255) NOT NULL,
    -- Add other fields as needed
    FOREIGN KEY (whoFirstSubscribed) REFERENCES users(screenname) ON DELETE CASCADE
);

Please note that using a screenname as a foreign key might not be the best practice, as it could lead to performance issues when your database grows. A better approach would be to use the id field from the users table as the foreign key in the feeds table.

If you have any specific questions or need help with SQL queries, please feel free to ask!

You can achieve this by using a GROUP BY clause in combination with the COUNT() function. The following SQL query will provide you with the desired result:

sql
SELECT u.screenname, COUNT(f.whoFirstSubscribed) as num_feeds
FROM users u
LEFT JOIN feeds f ON u.screenname = f.whoFirstSubscribed
GROUP BY u.screenname
ORDER BY num_feeds DESC;

This query will perform the following actions:

1. Perform a LEFT JOIN between the users table (aliased as u) and the feeds table (aliased as f) on the condition that the screenname in the users table matches the whoFirstSubscribed in the feeds table.
2. Group the results by the screenname field.
3. Count the number of feeds each user has as the first subscriber using the COUNT() function and assign this value to a new column called num_feeds.
4. Order the results by the num_feeds column in descending order (highest to lowest).

This query will return a list of all screennames along with the number of feeds they were the first to subscribe to, sorted from highest to lowest.