SELECT
  COUNT(*)
INTO
  :numberOfRecords 
FROM
  ProductEvidenceLink,
  EvidenceMetadata 
WHERE ProductEvidenceLink.evidenceMetadataID = :evidenceMetadataID 
  AND EvidenceMetadata.evidenceMetadataID = ProductEvidenceLink.evidenceMetadataID 
  AND ProductEvidenceLink.productID = :productID