distinct(d.d_id)
select distinct is NOT a function, and while use of those parentheses will not cause a syntax error they have absolutely no influence on the behaviour of select distinct; so ALL columns will be evaluated to produce a distinct set of values.
SELECT /* DISTINCT is this really needed? Don't use it unless needed */
d.d_id AS d
, v.v_id AS v
FROM D
LEFT JOIN V ON (d.d_id = v.v_id)
WHERE v.v_id IS NULL
OR d.d_id = 1
-- OR v.d_id = 1 -- not clear on which d_id you want to pass