MS Access 2016 VBA 在组合查询条件中为空

Question

Given a Query with the criteria that uses text boxes in access. It works fine.

Like IIf(IsNull([forms]![f_form]![txt_box]),"*",[forms]![f_form]![txt_box])

The above criteria works fine when a cell has a value. However, a lot of cells in the table which I search in, is null.

My best and logic shot was:

   Like IIf(IsNull([forms]![f_form]![txt_box]),"*",[forms]![f_form]![txt_box])
OR Like IIf(IsNull([forms]![f_form]![txt_box]),Is Null,[forms]![f_form]![txt_box])

However, this does not work.

If i just use "Or Is Null" then it returns all records where a cell is null even when i do a specific search.

Any suggestions?

BR, Emil.

Edit: The solution so far was to put in "-" in all null cells, but when the users leave a cell blank (Null), the record will never show up in the filter (Query). Hence I do not prefer this solution.

Answer 1

What I mean is this criteria:

[Forms]![f_form]![txt_box] OR ([Forms]![f_form]![txt_box] Is Null)

or if you want to support wildcard searches too (after all):

LIKE [Forms]![f_form]![txt_box] OR ([Forms]![f_form]![txt_box] Is Null)

Answer 2

I would suggest using NZ instead of IIF and IsNull combination,

SearchField Like Nz([forms]![f_form]![txt_box],'*')

Do you think that the txt_Box can have Zero length string instead of Null or possible that either of one can be there ? if so you can try following

SearchField like iif([forms]![f_form]![txt_box]='',' ',nz([forms]![f_form]![txt_box],' ')