Blank search fields should give me all records but it doesn't.

I have included a search form on my products_Results page, when I clear all data from the search form it seems to default to a one in the productStock which would equate to all items not in stock.

Here is the comparison list:

//comparison list additions
$WADbSearch1->addComparisonFromList("ProductCategoryID","S_ProductCategoryID","AND","=",1);
$WADbSearch1->addComparisonFromList("ProductSubCategoryID","S_ProductSubCategoryID","AND","=",1);
$WADbSearch1->addComparisonFromList("ProductSpecials","S_ProductSpecials","AND","=",1);
$WADbSearch1->addComparisonFromList("ProductStock","S_ProductStock","AND","=",1);
$WADbSearch1->addComparisonFromEdit("ProductName","S_ProductName","AND","Includes",0);
$WADbSearch1->addComparisonFromEdit("ProductSKU","S_ProductSKU","AND","=",0);