CREATE OR REPLACE FUNCTION get_feed_data(feed_key TEXT)
RETURNS JSON AS $$
DECLARE
  result JSON;
  sql_query TEXT;
BEGIN
  CASE feed_key
    WHEN 'movies' THEN
      sql_query := 'SELECT json_agg(feed ORDER BY (feed->>''date'')::timestamp DESC) FROM optimized_movies WHERE feed IS NOT NULL';
    WHEN 'books' THEN
      sql_query := 'SELECT json_agg(feed ORDER BY (feed->>''date'')::timestamp DESC) FROM optimized_books WHERE feed IS NOT NULL';
    WHEN 'posts' THEN
      sql_query := 'SELECT json_agg(feed ORDER BY (feed->>''date'')::timestamp DESC) FROM optimized_posts WHERE feed IS NOT NULL';
    WHEN 'links' THEN
      sql_query := 'SELECT json_agg(feed ORDER BY (feed->>''date'')::timestamp DESC) FROM optimized_links WHERE feed IS NOT NULL';
    WHEN 'allActivity' THEN
      sql_query := 'SELECT json_agg(feed ORDER BY (feed->>''date'')::timestamp DESC) FROM optimized_all_activity WHERE feed IS NOT NULL';
    WHEN 'syndication' THEN
      sql_query := 'SELECT json_agg(feed ORDER BY (feed->>''date'')::timestamp DESC) FROM optimized_syndication WHERE feed IS NOT NULL';
    ELSE
      RETURN NULL;
  END CASE;

  EXECUTE sql_query INTO result;
  RETURN result;
END;
$$ LANGUAGE plpgsql;