Multiple left outer join with same table allowed?

Question

I tried to convert below SQL in a more optimized way but it is giving error "Operand type clash: uniqueidentifier is incompatible with int". Could you please help me out

select E.EHOId, E.ReferenceId 'ReferenceNo',
(select Comp_Name from FoodAlertCRM.dbo.vCompanyPE where Comp_CompanyId = E.GroupId) 'Group',
(select Comp_Name from FoodAlertCRM.dbo.vCompanyPE where Comp_CompanyId = E.SiteId) 'Site',
 E.VisitDate as 'VisitDate',
(select Name from EHO_Dropdowns where ID = E.FollowupAction) 'FollowupAction',
(select Name from EHO_LocalAuthority where ID = E.LocalAuthority) 'LocalAuthority',
(select Name from EHO_Dropdowns where ID = E.[Status]) 'Status', 
(select Name from EHO_Dropdowns where ID = E.Position) 'Position',
(select Name from EHO_Dropdowns where ID = E.Structural) 'Structural',
(select Name from EHO_Dropdowns where ID = E.ConfidenceinManagement) 'ConfideninManagement',
(select Name from EHO_Dropdowns where ID = E.HygieneandSafety) 'HygieneandSafety',
(select Name from EHO_Dropdowns where ID = E.RoutineInspection) 'RoutineInspection',
(select Name from EHO_Dropdowns where ID = E.OutcomeofVisit) 'OutcomeofVisit',
e.OfficerName,e.FoodHygieneRating,e.ManageronDuty,e.Comments,
CASE E.AnnouncedVisit
 When  0 Then 'No'
 When 1 Then 'Yes'
 Else ''
ENd as 'AnnouncedVisit',
(select u.Username from FoodAlertCRM.dbo.CDB_User u where u.UserId = e.CreatedBy ) 'CreatedBy',
(select COUNT(EHOId) from EHO_Attachments where EHOId = E.EHOId) as 'AttachmentCount'
from EHO_Log E
where E.IsActive = 1 AND e.IsDeleted = 0 
Order by E.VisitDate desc

You see Above has alot of inner queries and performance will be very bad if there are thousand records. so i tried to get rid of inner queries.

select E.EHOId, E.ReferenceId 'ReferenceNo',
(select Comp_Name from FoodAlertCRM.dbo.vCompanyPE where Comp_CompanyId = E.GroupId) 'Group',
(select Comp_Name from FoodAlertCRM.dbo.vCompanyPE where Comp_CompanyId = E.SiteId) 'Site',
 E.VisitDate as 'VisitDate',
F.Name 'FollowupAction',L.Name 'LocalAuthority', St.Name 'Status',
P.Name 'Position', S.Name 'Structural', C.Name 'ConfideninManagement',
H.Name 'HygieneandSafety', R.Name 'RoutineInspection', O.Name 'OutcomeofVisit',
e.OfficerName,e.FoodHygieneRating,e.ManageronDuty,e.Comments,
CASE E.AnnouncedVisit
 When  0 Then 'No'
 When 1 Then 'Yes'
 Else ''
ENd as 'AnnouncedVisit',
(select u.Username from FoodAlertCRM.dbo.CDB_User u where u.UserId = e.CreatedBy ) 'CreatedBy',
(select COUNT(EHOId) from EHO_Attachments where EHOId = E.EHOId) as 'AttachmentCount'
from EHO_Log E
Left Outer Join EHO_Dropdowns St ON St.Id = E.[Status]
Left Outer Join EHO_Dropdowns F ON F.Id = E.FollowupAction
Left Outer Join EHO_Dropdowns L ON L.Id = E.LocalAuthority
Left Outer Join EHO_Dropdowns P ON P.Id = E.Position
Left Outer Join EHO_Dropdowns S ON S.Id = E.Structural
Left Outer Join EHO_Dropdowns C ON C.Id = E.ConfidenceinManagement
Left Outer Join EHO_Dropdowns H ON H.Id = E.HygieneandSafety
Left Outer Join EHO_Dropdowns R ON R.Id = E.RoutineInspection
Left Outer Join EHO_Dropdowns O ON O.Id = E.OutcomeofVisit
where E.IsActive = 1 AND e.IsDeleted = 0 
Order by E.VisitDate desc

Above code failed and i thought multiple Left outer joins are not allowed and i converted it into below query but still it fails

select E.EHOId, E.ReferenceId 'ReferenceNo',
(select Comp_Name from FoodAlertCRM.dbo.vCompanyPE where Comp_CompanyId = E.GroupId) 'Group',
(select Comp_Name from FoodAlertCRM.dbo.vCompanyPE where Comp_CompanyId = E.SiteId) 'Site',
 E.VisitDate as 'VisitDate',
D.Name 'FollowupAction',D.Name 'LocalAuthority', D.Name 'Status',
D.Name 'Position', D.Name 'Structural', D.Name 'ConfideninManagement',
D.Name 'HygieneandSafety', D.Name 'RoutineInspection', D.Name 'OutcomeofVisit',
e.OfficerName,e.FoodHygieneRating,e.ManageronDuty,e.Comments,
CASE E.AnnouncedVisit
 When  0 Then 'No'
 When 1 Then 'Yes'
 Else ''
ENd as 'AnnouncedVisit',
(select u.Username from FoodAlertCRM.dbo.CDB_User u where u.UserId = e.CreatedBy ) 'CreatedBy',
(select COUNT(EHOId) from EHO_Attachments where EHOId = E.EHOId) as 'AttachmentCount'
from EHO_Log E
Left Outer Join EHO_Dropdowns D ON D.Id = E.[Status] AND D.Id = E.FollowupAction
AND D.Id = E.LocalAuthority AND D.Id = E.Position AND D.Id = E.Structural
AND D.Id = E.ConfidenceinManagement AND D.Id = E.HygieneandSafety
AND D.Id = E.RoutineInspection AND D.Id = E.OutcomeofVisit
where E.IsActive = 1 AND e.IsDeleted = 0 
Order by E.VisitDate desc

Any idea guys? both of the new queries return error "Operand type clash: uniqueidentifier is incompatible with int".

Answer 1

I think the cause may be this line:

Left Outer Join EHO_Dropdowns L ON L.Id = E.LocalAuthority

Try changing it to be:

Left Outer Join EHO_LocalAuthority L ON L.Id = E.LocalAuthority

Answer 2

Mulitple Outer Join on Same Table :

Solution:

please use nvl on outer join fields

NVL(EHO_Dropdowns(+),EHO_LocalAuthority(+)) = E.LocalAuthority