Question

SQL Experts,

Is there an efficient way to group runs of data together using SQL?
Or is it going to be more efficient to process the data in code.

For example if I have the following data:

ID|Name 01|Harry Johns 02|Adam Taylor 03|John Smith 04|John Smith 05|Bill Manning 06|John Smith 

I need to display this:

Harry Johns Adam Taylor John Smith (2) Bill Manning John Smith 

@Matt: Sorry I had trouble formatting the data using an embedded html table it worked in the preview but not in the final display.

Answer 1

Try this:

select n.name,      (select count(*)       from myTable n1      where n1.name = n.name and n1.id >= n.id and (n1.id <=         (         select isnull(min(nn.id), (select max(id) + 1 from myTable))         from myTable nn         where nn.id > n.id and nn.name <> n.name         )      )) from myTable n where not exists (    select 1    from myTable n3    where n3.name = n.name and n3.id < n.id and n3.id > (             select isnull(max(n4.id), (select min(id) - 1 from myTable))             from myTable n4             where n4.id < n.id and n4.name <> n.name             ) ) 

I think that’ll do what you want. Bit of a kludge though.

Phew! After a few edits I think I have all the edge cases sorted out.