Problems with DISTINCT command

I am using next SQL command

SELECT DISTINCT
parid,
parnombre,
partuser
FROM “public”.parametros
LEFT JOIN “public”.parametros_categorias
ON “public”.parametros.parid = “public”.parametros_categorias.parid
LEFT JOIN “public”.parametro_modulo
ON “public”.parametros.parid = “public”.parametro_modulo.parid
WHERE msiid = [iMsiid]

DISTINCT is not working and when I activate the debug mode this command is complety ignored

I am using postgre database

Thanks

Look at this thread and try the solution from post #8.