How to find the first value in a column

[ambuj2k50]

Hi Cognos Gurus,

Lets say the output of a column is

Column A
abc
def
cde

What is the expression to create a data item that will give only the output abc.

Thanks in advance.

[blom0344]

the concept 'first' is hazardous, cause database are not supposed to store data in an ordered fashion. By selecting data we imply a sorting through the query. 

Solutions either involve olap style functions like rownumber() or running aggregates like running-count.  You then need to apply the proper filter with 'after auto-aggregation' set to make sure you can filter . Thare are lots of posts dealing with this