Question

I’ve received data from an external source, which is in a summarised format. I need a way to disaggregate this to fit into a system I am using.

To illustrate, suppose the data I received looks like this:

receivedTable:

Age     Gender     Count
40      M          3
41      M          2

I want this is a disaggregated format like this:

systemTable:

ID      Age        Gender
1       40         M          
2       40         M 
3       40         M 
4       41         M          
5       41         M 

Thanks
Karl

Answer 1

Depending of the range of your count you could use a lookup table that holds exactly x records for each integer x. Like this:

create table counter(num int)
insert into counter select 1

insert into counter select 2
insert into counter select 2

insert into counter select 3
insert into counter select 3
insert into counter select 3

insert into counter select 4
insert into counter select 4
insert into counter select 4
insert into counter select 4

then join with this table:

create table source(age int, gender char(1), num int)
insert into source select 40, 'm', 3
insert into source select 30, 'f', 2
insert into source select 20, 'm', 1

--insert into destination(age, gender)
    select age, gender
    from source
        inner join counter on counter.num = source.num