SELECT
    COUNT(tt.*) AS page_count
    
FROM

    time_tracker AS tt
        LEFT JOIN
    tasks AS tk ON tt.element_id = tk.task_id AND tt.element_type=2
        LEFT JOIN
    projects AS pr ON tt.element_id = pr.project_id AND tt.element_type=1
    
                    
   

WHERE

    tt.user_id = '##user_id##'
    AND (pr.project_id='##project_id##' OR tk.project_id='##project_id##')
    ##narrow_by##


GROUP BY tt.time_id