SQLite 3.8

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create table operating_system (app_id  integer,
                               name    varchar(20),
                               app_count  integer);
create table operate (app_id  integer,
                      operating_system_name  varchar(20));
insert into operating_system(app_id, name)
  select 1, 'Windows' union all
  select 2, 'Linux' union all
  select 3, 'DOS'
insert into operate (app_id, operating_system_name)
  select 1, 'Windows' union all
  select 2, 'Linux' union all
  select 3, 'DOS' union all
  select 4, 'Windows' union all
  select 5, 'DOS' union all
  select 6, 'Windows'
SELECT OPERATING_SYSTEM.NAME, COUNT(OPERATE.App_ID) AS App_Count 
     FROM OPERATING_SYSTEM , OPERATE WHERE OPERATING_SYSTEM.Name = OPERATE.Operating_System_Name
     GROUP BY OPERATING_SYSTEM.Name
     ORDER BY OPERATING_SYSTEM.APP_ID


name
App_Count


Windows
3

Linux
1

DOS
2


UPDATE OPERATING_SYSTEM
SET App_Count =
    (SELECT COUNT(OPERATE.App_ID) AS App_Count
     FROM OPERATE
     WHERE OPERATING_SYSTEM.Name = OPERATE.Operating_System_Name
     GROUP BY OPERATE.Operating_System_Name);
select *
  from operating_system
  ORDER BY APP_ID


app_id
name
app_count


1
Windows
3

2
Linux
1

3
DOS
2