demo, Sql Server - rextester

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create table t (MyName varchar(10), MyDate date);

insert t values 
('ABC', '2017-04-11'), 
('DEF', '2017-04-11'), 
('GHJ', '2017-04-11'), 
('ABC', '2017-04-10'), 
('DEF', '2017-04-10'), 
('GHJ', '2017-04-10'), 
('ABC', '2017-04-07'), 
('GHJ', '2017-04-07');

GO
create function myFun(@start date, @end date) 
returns @result table (MyName varchar(10), MyDate date, Ins bit) as
begin
;
    with dates as (
        SELECT  DATEADD(DAY, nbr - 1, @start) dt
        FROM    ( SELECT    ROW_NUMBER() OVER ( ORDER BY c.object_id ) AS Nbr
                  FROM      sys.columns c
                ) nbrs
        WHERE   nbr - 1 <= DATEDIFF(DAY, @start, @end)
    ), last_avail as (
        select dates.dt, max(t.MyDate) prev_dt
        from dates join t on dates.dt >= t.MyDate
        group by dates.dt
    ), empty as (
        select * from last_avail where dt <> prev_dt
    )
    insert @result (MyName, MyDate, Ins)
    select MyName, MyDate, 0 from t
    union all
    select t.MyName, x.dt, 1
    from empty x join t on x.prev_dt = t.MyDate;
    
    return;
end
GO

declare @start date, @end date;

set @start = '2017-04-07';
set @end = '2017-04-11';

select * from dbo.myFun(@start, @end) order by MyDate desc, MyName asc;

View schema
Execution time: 0,05 sec, rows selected: 14, rows affected: 8, absolute service time: 0,19 sec