SELECT
IssueTracker_Issues.IssueId, 
IssueTracker_Issues.IssueTitle As 'Issue Title',
IssueTracker_ProjectCategories.CategoryName As 'Category', 
IssueTracker_Users.DisplayName As 'Assigned To',
IssueTracker_Users.DisplayName As 'Owned By'

FROM IssueTracker_Issues 

LEFT JOIN IssueTracker_ProjectCategories ON IssueTracker_Issues.IssueCategoryID=IssueTracker_ProjectCategories.CategoryID
LEFT JOIN IssueTracker_Users ON (IssueTracker_Issues.IssueAssignedID=IssueTracker_Users.UserId
AND IssueTracker_Issues.IssueOwnerID=IssueTracker_Users.UserId)