Excluding Records Based On A Number Of Criteria

Hello all,

I'm having some difficulty obtaining the answers I want from my query. I'd have been more comfortable using filters in excel to find the answers, but my dataset is too large in this instance.

I devised a query which I thought should achieve the results, but based on a subset analysed in Excel the answers are significantly different.

My table has about thirty fields, the query I've produced is this:
SELECT AH_orphans.Product, AH_orphans.Comments, AH_orphans.ESP, AH_orphans.[ESP Parts],
<snip, all other fields in table>
FROM AH_orphans
WHERE (((AH_orphans.ESP)="n") AND ((AH_orphans.FRU)="y") AND ((AH_orphans.EntitlementName) Like "*uptime*") AND ((AH_orphans.Account) Like "nation*") AND ((AH_orphans.Type) Like "Primar*") AND ((AH_orphans.[Is a parent?])="#n/a")) OR (((AH_orphans.ESP) Is Null) AND ((AH_orphans.FRU) Is Null) AND ((AH_orphans.EntitlementName) Like "*uptime*") AND ((AH_orphans.Account) Like "nation*") AND ((AH_orphans.Type) Like "Primar*") AND ((AH_orphans.[Is a parent?])="#n/a"));

What I'm hoping for is the subset which match the following conditions:
- ESP field is not "Y". Possible values Y, N, null
- FRU field is not "N". Possible values Y, N, null
- Only those records from EntitlementName which include the substring 'uptime'
- Only those records from Account which start with the subtring nation
- Only those records from Type which include the substring primar
- Only those records from [Is a parent?] which equal #N/A.

Asking the same questions in Excel I get around 1.5k records. If I use the quoted query on the same dataset in Access I get precisely 11.

Thanks for reading this far! If anyone can spot the flaw/s in my query, or indeed advise that I'm going at it completely the wrong way I'd be very grateful of some advice.

Cheers,
Alex