Dividing two calculated values in mySQL select -

here's query is:

select  a.cartodb_id cartdb_id, a.identifier store, (select count(*) full_data_for_testing_deid_2) ,count(b.*)   customer_count  demo_locations_table a, full_data_for_testing_deid_2 b  st_dwithin(a.the_geom::geography,b.the_geom::geography,16093)  group a.cartodb_id 

and here's comes back:

| cartdb_id | store           | count | customer_count | |-----------|-----------------|-------|----------------| | 1         | store number: 1 | 32085 | 30             | | 2         | store number: 2 | 32085 | 283            | | 3         | store number: 3 | 32085 | 609            | | 4         | store number: 4 | 32085 | 61             | | 5         | store number: 5 | 32085 | 325            | 

in case, count equals total number of customers (one row per customer) in table. want column shows percentage of customers per store: customer_count divided count, can't figure out how integrate query. ps: don't need count column. included reference.

thanks.

select  a.cartodb_id cartdb_id, a.identifier store, count(b.*)   customer_count , count(b.*)/(select count(*) full_data_for_testing_deid_2)*100 percentage demo_locations_table a, full_data_for_testing_deid_2 b  st_dwithin(a.the_geom::geography,b.the_geom::geography,16093)  group a.cartodb_id