Cumulative count in mysql

Here's one possible solution. Create a function that takes a date as an input and calculates the cumulative count for that date and then returns the count. Then in your original query, replace the count(some_field) with a call to the function, passing the function the row's date.

create or replace function calc_cumulative_count(input_date DATE)
  return   LONG
as
  cumulative_count     LONG;
  select count(your_field_name)
    into cumulative_count
    from your_table
   where some_date_field <= input_date;

  return cumulative_count;
end calc_cumulative_count;
/

If your exisiting query is

select some_date_field
      ,count(your_field_name)
  from your_table
 group by some_date_field
;

this can be changed to

select distinct some_date_field
      ,calc_cumulative_count(some_date_field)
  from your_table
;