Query Using Input From A Form with A Checkbox - ms-access-2007

Question

Thank you, ahead of time, to everyone, for your time and attention.
I am doing a very simple database for my job, that was too large to fit into an excel spreadsheet, which is what we usually use here. I apologize ahead of time, as I have very limited knowledge of access, but have to figure this out.
I have about 1,150,000 records and need to be able to search by the following criteria: Part Number (txtPK), Step (txtStep), Skipped Percentage (txtPer), and Bottleneck? (chkARD); ARD is in the database as "Y" or "N".
This code worked to show either only Y or only N:
IIf([Forms]![Skips_Form]![chkARD],"Y", "N")
However, when I tried to adapt it to show "*" instead of "N" it returns no records, instead of all records.
IIf([Forms]![Skips_Form]![chkARD],"Y", "*")
My desire is to show only the records with "Y" when the checkbox is checked,
and to show all records when it is not checked.

Answer 1

Presumably you are using these iif statements within the where clause of your query, in conjunction with the = operator - something like:
select *
from YourTable
where ARD = IIf([Forms]![Skips_Form]![chkARD],"Y", "*")
If this is indeed the case, then, when the else argument of the iif statement is returned, the SQL statement becomes:
select *
from YourTable
where ARD = "*"
Hence, this will return records for which the ARD field has a literal value of "*".
Instead, you should either use the like operator, which will allow wildcards such as the asterisk to match any value, e.g.:
select *
from YourTable
where ARD like IIf([Forms]![Skips_Form]![chkARD],"Y", "*")
Or, use some simple boolean logic, such as:
select *
from YourTable
where (not [Forms]![Skips_Form]![chkARD]) or ARD="Y"

Answer 2

Complete Working SQL Code
Thank you Lee Mac
SELECT Data.POS, Data.PK, Data.[Step], Data.[ARD?], Skips.Skips, Skips.Total,
Skips.[Skips %], Data.[OPERATION DESCRIPTION], Data.CHARGE_NUMBER, Data.[MDM_PN],
Data.[PlanVer], Data.[PlanRev], Data.[Task_Desc], Data.[Prod Version]
FROM Data INNER JOIN Skips ON Data.POS = Skips.POS
WHERE
(((Data.POS) Like "*" & [Forms]![Skips_Form]![txtPK] & "*")
AND ((Data.[Step]) Like "*" & [Forms]![Skips_Form]![txtStep] & "*")
AND ((Data.[ARD?]) Like IIf([Forms]![Skips_Form]![chkARD],"Y","*"))
AND ((Skips.[Skips %])>=[Forms]![Skips_Form]![txtPer]))
OR
(((Data.POS) Like "*" & [Forms]![Skips_Form]![txtPK] & "*")
AND ((Data.[Step]) Like "*" & [Forms]![Skips_Form]![txtStep] & "*")
AND ((Data.[ARD?]) Like IIf([Forms]![Skips_Form]![chkARD],"Y","*")))
ORDER BY Skips.[Skips %];