PL/PGSQL help for getting number of rows matched.

Hi,

We need to implement following logic efficiently.

SELECT * from some_table where .... [ Query 1 ]

IF rows_matched = 1 THEN

use the single row that matched.

ELSIF

loop thru the results of [Query 1]

END IF;

Currently i am doing select count(*) for getting rows_matched
in the top and repeating the same query in both branches of IF
to get the data of matching rows.

I have tried GET DIAGNOSTICS ROW_COUNT but for
"SELECTS" if returns 0 or 1 based on matching

I am sure there exists better methods. Kindly post a link
to better documentation of pl/pgsql or point out section in
the standard docs that discuss this issue.

Regds
Mallah.