PL/pgSQL: SELECT INTO only if result count = 1

Tarlika Elisabeth Schmitz <postgresql6@xxxxxxxxxxxxxxxxxxxx> · Sat, 27 Aug 2011 21:14:21 +0100

Hello,

In a PL/pgSQL trigger function, I try to select a record from table
"town" below.

I am only interested in the result if the returned result set contains
exactly one result.
If there is more than one result, I want to log the fact.

EXAMPLE pseudo code

select 
country_fk, region_fk, id
from town 
where name = 'Newcastle'

if found and count = 1 
  populate  country_id, region_id, town_id
else
  raise notice 'ambiguous %', town.name

=======

CREATE TABLE town
(
  country_fk character varying(3) NOT NULL,
  region_fk character varying(3) NOT NULL,
  id serial NOT NULL,
  "name" character varying(60) NOT NULL,
  CONSTRAINT ...
)
-- 

Best Regards,
Tarlika Elisabeth Schmitz

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