How no to select lines with NULL values

Question

Hi,
I am not a newbie newbie in SQL but I do not understand why I cannot retrieve the lines where there are null values.
The table observatoire.fiche has 2 columns with default values set to NULL : total_heures, and total_heures_exceptionnelles. These are numeric types columns.
I want not to select lines where :
total_heures equal NULL AND total_heures_exceptionnelles = NULLI have tried this but I do get an "Invalid relational operator" error message.
select a.nom || ' ' || a.prenom d, a.agent_id r
from   OBSERVATOIRE.AGENT a, observatoire.fiche b
where  a.agent_id = b.agent_id
and    b.total_heures NOT NULL AND total_heures_exceptionnelles NOT NULL
group by a.nom, a.prenom, a.agent_id
order by a.nomCould you help me ?
Thank you for your kind answers.

Answer 1

Satyaki_De wrote:
I think this is not the good way to do it. Did you check my solution? It should work the same output as your solution.Really ?
test@ORA10G>
test@ORA10G> -- (1)
test@ORA10G> with t as (
  2    select 1 as x, 10 as total_heures, null as total_heures_exceptionnelles from dual union all
  3    select 1, null, 20   from dual union all
  4    select 1, null, null from dual union all
  5    select 1, 30, 40     from dual)
  6  --
  7  select x, total_heures, total_heures_exceptionnelles
  8  from   t
  9  where  x = 1
10  AND NOT ( total_heures IS  NULL
11            AND
12            total_heures_exceptionnelles IS NULL
13          );
         X TOTAL_HEURES TOTAL_HEURES_EXCEPTIONNELLES
         1           10
         1                                        20
         1           30                           40
test@ORA10G>
test@ORA10G> -- (2)
test@ORA10G> with t as (
  2    select 1 as x, 10 as total_heures, null as total_heures_exceptionnelles from dual union all
  3    select 1, null, 20   from dual union all
  4    select 1, null, null from dual union all
  5    select 1, 30, 40     from dual)
  6  --
  7  select x, total_heures, total_heures_exceptionnelles
  8  from   t
  9  where  x = 1
10  AND    total_heures IS NOT NULL
11  AND    total_heures_exceptionnelles IS NOT NULL;
         X TOTAL_HEURES TOTAL_HEURES_EXCEPTIONNELLES
         1           30                           40
test@ORA10G>
test@ORA10G>isotope