display orphan records

I have the following query:

select g.Agency,g.Goal,o.Objective,p.PI,a.[Activity Name] from tblOrgGoals G
Inner Join tblOrgObjectives O on G.GoalID = O.GoalID
Inner Join tblOrgPI P on O.ObjectiveID = P.ObjectiveID
Inner Join tblOrgActivities A on P.PIID = A.PIID


It only gives me records that are complete having all tables connected with actual records.  However, I have some tables that are incomplete.  For example, tblOrgActivities does not have and Activity for every record in tblOrgObjectives.

Is there a way to query all the above records and show even orphan records.  (See attachment highlighted in yellow)
example.xlsx
al4629740Asked:
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SharathConnect With a Mentor Data EngineerCommented:
change INNER JOIN to LEFT JOIN
select g.Agency,g.Goal,o.Objective,p.PI,a.[Activity Name] from tblOrgGoals G 
LEFT Join tblOrgObjectives O on G.GoalID = O.GoalID
LEFT Join tblOrgPI P on O.ObjectiveID = P.ObjectiveID
LEFT Join tblOrgActivities A on P.PIID = A.PIID

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al4629740Author Commented:
What is the difference between INNER JOIN and LEFT JOIN?

Does this display all possible records in all the tables?
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SharathConnect With a Mentor Data EngineerCommented:
It displays all records from the first table and matching records from the rest of tables.
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DBAduck - Ben MillerConnect With a Mentor Principal ConsultantCommented:
A LEFT JOIN matches all the rows in both tables and for those that do not exist in the RIGHT table, it shows NULLs.

So you can tell which ones do not match up by using something like this:

select g.Agency,g.Goal,o.Objective,p.PI,a.[Activity Name] 
from tblOrgGoals G 
LEFT Join tblOrgObjectives O on G.GoalID = O.GoalID
WHERE O.GoalID IS NULL

Open in new window


This will show you which OrgGoals rows do not have any rows in the OrgObjectives table.
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Vikas GargConnect With a Mentor Business Intelligence DeveloperCommented:
Hi,

The below query will give you the result as you require

select g.Agency,g.Goal,o.Objective,p.PI,a.[Activity Name] from tblOrgGoals G
Inner Join tblOrgObjectives O on G.GoalID = O.GoalID
LEFT Join tblOrgPI P on O.ObjectiveID = P.ObjectiveID
LEFT Join tblOrgActivities A on P.PIID = A.PIID

and if you want only those records which are not in  tblOrgPI  and tblOrgActivities then

select g.Agency,g.Goal,o.Objective,p.PI,a.[Activity Name] from tblOrgGoals G
Inner Join tblOrgObjectives O on G.GoalID = O.GoalID
LEFT Join tblOrgPI P on O.ObjectiveID = P.ObjectiveID
LEFT Join tblOrgActivities A on P.PIID = A.PIID

WHERE  p.PI IS NULL AND a.[Activity Name] IS null
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al4629740Author Commented:
Could you help me a little more and show whats the difference between these two queries when it comes to the Join statements

select g.Agency,g.Goal,o.Objective,p.PI,a.[Activity Name] from tblOrgGoals G 
LEFT Join tblOrgObjectives O on G.GoalID = O.GoalID
LEFT Join tblOrgPI P on O.ObjectiveID = P.ObjectiveID
LEFT Join tblOrgActivities A on P.PIID = A.PIID

Open in new window


select g.Agency,g.Goal,o.Objective,p.PI,a.[Activity Name] from tblOrgGoals G
Inner Join tblOrgObjectives O on G.GoalID = O.GoalID
LEFT Join tblOrgPI P on O.ObjectiveID = P.ObjectiveID
LEFT Join tblOrgActivities A on P.PIID = A.PIID

Open in new window


select g.Agency,g.Goal,o.Objective,p.PI,a.[Activity Name] from tblOrgGoals G 
Inner Join tblOrgObjectives O on G.GoalID = O.GoalID
Inner Join tblOrgPI P on O.ObjectiveID = P.ObjectiveID
Inner Join tblOrgActivities A on P.PIID = A.PIID

Open in new window


To me the first two pull up the same data, but the third is different.
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DBAduck - Ben MillerConnect With a Mentor Principal ConsultantCommented:
Again, the first one will join tblOrgGoals with the other 3 and for every row in tblOrgGoals it will display a row, but for the columns that are in the tblOrgObjectives, tblOrgPI and tblOrgActivities it will show values for only those rows that have a match for each key in the ON clause and NULL for those values in those tables that do not have a match in the ON clause.

The 2nd one is close except that the first 2 tables will be joined by the ON clause and will technically be like 1 table with those rows that match the ON clause and then this table will be joined with the other 2 tables as above.

The 3rd one is INNER join only which means that it will only show rows that have all the JOIN ON clauses met with keys existing in both tables.  Any key that does not have a match on the left and right tables will be filtered out.
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