android - Merge different rows to one and count how many rows were merged -

let's have following rows in table:

externalid   count   descriptor    1           1        val-1    1           1        val-2    2           1        val-3    2           1        val-4    2           1        val-5    2           1        val-6    3           1        val-7 

i need accomplish this:

externalid   count       descriptor    1           2        val-1, val-2    2           3        val-3, val-4, val-5    3           1        val-7 

would possible?

it possible perhaps not done thing/best utilisation of available features of relational databases.

this appears case utilising advtanges of relationships.

how considering table external id's , table descriptors , link table (assocciative table or many other names uses tables tie relationships).

e.g.

create table externals (_id primary integer key, extid integer) create table descriptors (_id primary integer key, descriptor text) create table link_externals_to_descriptors (external_ref integer not null, descriptor_ref integer not null) 

so above have (note i've used id's 10-12 , 100-106 distinguish them illustration purposes):-

externals table

 _id       extid   10        1  11        2  12        3  99        9 

descriptors table

_id        descriptor 100        val-1 101        val-2 102        val-3 103        val-4 104        val-5 105        val-6 106        val-7 

link table (link_externals_to_descriptors)

external_ref         descriptor_ref 1                    100 1                    101 2                    102 2                    103 2                    104 3                    106 99                   100 99                   102 99                   104 99                   105 99                   107 

this may seem , may overly complex copes one-many, many-one , many-many relationships between externalid's , descriptors.

i.e. 99 equivalent to

9                   val-1, val-3, val-5, val-6, val-7 

(all except val-6 being used others)

there no need merge or un-merge, split csv individual descriptors. want. e.g.

select * link_externals_to_descriptors external_ref = 99; 

being used drive query return cursor who's count (number of rows) number of descriptors external id.

as such, following used count , descriptors (outputting info log) :-

cursor csr = db.query("link_externals_to_descriptors",     null,     "external_ref=?",     new string[]{"99"},     null,null,null); int my_count_of_descriptors = csr.getcount() log.d("myinfo","the number of descriptors extid 99 is" +     integer.tostring(my_count_of_descriptors) +     " are:-"); while(csr.movetonext) {     log.d("myinfo","\t" + csr.getstring(csr.getcolumnindex("descriptor_ref"))); } csr.close();