T-SQL Execute Recursion for Each Value in Multiple Columns - sql

Question

I have a dataset with two columns. A person in the first column may be in the span of control of a person in the second column (i.e. everyone is in Michael's span of control, Dwight & Stanley are in Jim's span of control):
source_id source target_id target
1 Michael Scott 5 Kelly Kapoor
3 Dwight Schrute 2 Jim Halpert
4 Stanley Hudson 2 Jim Halpert
2 Jim Halpert 5 Kelly Kapoor
I have a table that lists each person and their supervisor:
person_id person supervisor_id supervisor
1 Michael Scott 0 None
2 Jim Halpert 1 Michael Scott
3 Dwight Schrute 2 Jim Halpert
4 Stanley Hudson 2 Jim Halpert
6 Ryan Howard 1 Michael Scott
5 Kelly Kapoor 6 Ryan Howard
I have a block of code that uses recursion to find a single person's span of control from the preceding table:
with anchor as
(
select person_id, supervisor_id from table where unique_id = #ID
union all
select a.person_id, a.supervisor_id
from table a
inner join Anchor b ON b.person_id = a.supervisor_id
)
select a.person_id
from anchor a
This block of code can be turned into a stored procedure or a function. Running it for Jim (for example), returns:
person_id
3 (Dwight Schrute)
4 (Stanley Hudson)
How do I compare each value in the initial dataset (from both the source and target columns) to the values in the column returned by the preceding block of code? In other words, for each row in source, I need to check if that name is within the span of control of target. In addition, for each row in target, I need to check if that name is within the span of control of source.
Desired End Result:
source_id source target_id target isEitherPersonInOther'sSOC
1 Michael Scott 5 Kelly Kapoor Yes
3 Dwight Schrute 2 Jim Halpert Yes
4 Stanley Hudson 2 Jim Halpert Yes
2 Jim Halpert 5 Kelly Kapoor No
I know iterations are bad (i.e. running the stored procedure for each row with a cursor or while loop). I also know cross apply and a function together may work, but I have been unable to figure my way through that.
Thank you for any insight you all may have!

Answer 1

What it looks like you need is to take your recursive CTE and output ID pairs into a temp table. I'm picturing something like this:
DECLARE #id int
DECLARE cx CURSOR FOR
SELECT person_id FROM PersonSupervisor
CREATE TABLE #tmpPS (Supervisor int, personInChain int)
OPEN cx
FETCH NEXT FROM cx
INTO #id
WHILE ##FETCH_STATUS = 0
BEGIN
with anchor as
(
select person_id, supervisor_id from table where unique_id = #ID
union all
select a.person_id, a.supervisor_id
from table a
inner join Anchor b ON b.person_id = a.supervisor_id
)
INSERT INTO #tmpPS
select #id, a.person_id
from anchor a
FETCH NEXT FROM cx
INTO #id
END
Close cx
Deallocate cx
This creates a table of all relationships, recursively expanded. Then you can output whether any given person is either above or below a given other person with this subquery. Add it to whatever query outputs your base grid:
SELECT
SourceId,
Source,
TargetId,
Target,
CASE
WHEN EXISTS (SELECT 1 FROM #tmpPS WHERE Supervisor = SourceId and PersonInChain = TargetId)
THEN 'Yes'
WHEN EXISTS (SELECT 1 FROM #tmpPS WHERE Supervisor = TargetId and PersonInChain = SourceId)
THEN 'Yes'
ELSE 'No'
END as [isEitherPersonInOther'sSOC]
FROM ....
This also implies a version of this where you can separate the relationships out - If the first query, the TargetId is a subordinate of the SourceId. If the second query, then TargetId is a superior to SourceId.

Answer 2

There has to be a better way to do this but this is definitely one way to go about it -- note the code creates permanent tables to use in a function:
create table dbo.[source]
(
source_id int,
[source] nvarchar(500),
target_id int,
[target] nvarchar(500)
)
insert into [source]
select 1, 'Michael Scott', 5, 'Kelly Kapoor'
union all select 3,'Dwight Schrute',2,'Jim Halpert'
union all select 4 ,'Stanley Hudson',2,'Jim Halpert'
union all select 2 ,'Jim Halpert',5,'Kelly Kapoor'
create table dbo.supervisors
(
person_id int,
person nvarchar(500),
supervisor_id int,
supervisor nvarchar(500)
)
insert into dbo.supervisors
select 1,'Michael Scott', 0,'None'
union all select 2,'Jim Halpert',1,'Michael Scott'
union all select 3,'Dwight Schrute',2,'Jim Halpert'
union all select 4,'Stanley Hudson',2,'Jim Halpert'
union all select 6,'Ryan Howard',1,'Michael Scott'
union all select 5 ,'Kelly Kapoor',6,'Ryan Howard'
go
create function dbo.fn_isinspanofcontrol
(
#sourceid int,
#targetid int
)
RETURNS varchar(1)
as
begin
declare #retVal varchar(1)
declare #tbl table
(
person_id int
)
;with anchor as
(
select person_id, supervisor_id from supervisors where person_id = #sourceid
union all
select a.person_id, a.supervisor_id
from supervisors a
inner join Anchor b ON b.person_id = a.supervisor_id
)
insert into #tbl
select a.person_id
from anchor a
where
a.person_id = #targetid
;with anchor as
(
select person_id, supervisor_id from supervisors where person_id = #targetid
union all
select a.person_id, a.supervisor_id
from supervisors a
inner join Anchor b ON b.person_id = a.supervisor_id
)
insert into #tbl
select a.person_id
from anchor a
where
a.person_id = #sourceid
if exists( select 1
from #tbl
)
begin
set #retVal = 'Y'
end
else
begin
set #retVal = 'N'
end
return #retVal
end
select
*, dbo.fn_isinspanofcontrol(source_id,target_id)
from [source]