Please share your code for this search form.

Yeah, without some screenshots or to see what you've got going on there, it's very hard to tell what the problem is. If you're following a specific video or a lesson, please give us the specifics and a time index.

I think I understand what the question is.  Suppose we have this table:

FirstName     LastName    Occupation
Neil          Simon       Playwright
Simon         Callow      Actor
Simone        Signoret    Actress
Simone        Simon       Actress
Bjork                     Actress/Singer
Cher                      Actress/Singer

And we want to find people who are actresses with last names that are either "Simon" or blank.  In this case, the query needs to return the last 3 rows above.  And the query should be:

     SELECT * FROM Table1 WHERE Occupation Is Like "*Actress*" AND (LastName = "Simon" OR LastName Is Null)

Basically, this is about using AND and OR correctly.  And if the OR condition needs to be evaluated first, as is the case above, it needs to be enclosed with parentheses.

This is the where part from the SQL statement from my query:
WHERE (((Adresse_T.NoCivique) Like "*" & [forms]![RechAdresse_F]![RechNoCivique] & "*") AND ((Adresse_T.Rue) Like "*" & [forms]![RechAdresse_F]![RechRue] & "*") AND ((Adresse_T.NoApp) Like "*" & [forms]![RechAdresse_F]![RechApp] & "*" Or (Adresse_T.NoApp) Is Null) AND ((Adresse_T.Ville) Like "*" & [forms]![RechAdresse_F]![RechVille] & "*") AND ((Adresse_T.CodePostal) Like "*" & [forms]![RechAdresse_F]![RechCP] & "*") AND ((Adresse_T.AdresseID) Like "*" & [forms]![RechAdresse_F]![RechAdresseID] & "*") AND ((Adresse_T.RaisonSociale) Like "*" & [forms]![RechAdresse_F]![RechRaison] & "*" Or (Adresse_T.RaisonSociale) Is Null) AND ((Adresse_T.Province) Like "*" & [forms]![RechAdresse_F]![RechProv] & "*") AND ((Adresse_T.Pays) Like "*" & [forms]![RechAdresse_F]![RechPays] & "*") AND ((Adresse_T.TypeRue) Like "*" & [forms]![RechAdresse_F]![RechTypeRue] & "*"));

I have a problem with RechApp and RechRaison because I will get null values in both fields when searching for records but I don't want them, see the picture

In the screenshot, I don't want records 2, 3 and 4...

What is it about those records that you don't want? What's the criteria you're looking for in English? Your SQL statement is just a jumble to me. Sorry.

Hi Simon, if you sometimes want to include null and sometimes not, then you can only use OR Is Null when you want to include null, and cannot use OR Is Null when you don't.  If you want your App field to include only "5" but not blanks, then you have to delete "OR NoApp Is Null" from your SQL.  Later if you want to include "5" and blanks, put it back in.  What's more, the user needs to have a way to "tell" Access whether to include blanks in the search results or not.  Put a checkbox for "Include blanks" on the form, for EVERY field that you want to do this for.  Then you use VBA to dynamically add (or not add) OR Is Null.  This is not a trivial task, naturally, so maybe that's why Richard doesn't include this in his Search Form 2.0 video.  But it is needed to do what you are describing, as far as I know.  I do a similar thing in my app too (see picture below).  I let the user specify "Empty" specifically if they need to include empty fields in the results.  If the user leaves an entry blank, that means any value of that field will be returned.