SQL Server – Good Way to Aggregate on Different Columns Within the Same Query

This is a great example of how the Window Functions can be used. Based on your data, I'm assuming you want to do this for every unique LINE_NO. I'll leave it to you to format the percentage column.

SELECT      LINE_NO,
            E_FIELD,
            F_FIELD,
            G_FIELD,
            HSA_STATUS,
            FAMILY,
            CACHE_FAMILY,
            COUNT(*) AS CT,
            COUNT(*) / SUM(COUNT(*) * 1.0) OVER (PARTITION BY LINE_NO)

FROM        TX_HSA_SUMM

GROUP BY    LINE_NO,
            E_FIELD,
            F_FIELD,
            G_FIELD,
            HSA_STATUS,
            FAMILY,
            CACHE_FAMILY

You could just use the SQL statement:

SELECT sum(out_nb_comm) AS sum_out_nb_comm
FROM   count_comm($in_id_alias);

Or, if you want to wrap it in a function, a simple SQL function does the job:

CREATE OR REPLACE FUNCTION sum_count_comm(in_id_alias int)
   RETURNS int AS
$func$
SELECT sum(out_nb_comm)::int
FROM   count_comm($1));
$func$ LANGUAGE sql;