Why is my table populating NULL instead of blank? - sql

Question

I am trying to figure out why my Eclassification column is still populating NULL instead of a blank value when using the below query in a stored procedure. Originally I just had the Case statement but since that wasn't working I tried adding in the ISNULL as well, but my table will only populate Green or NULL.
update ft
set EClassification = case when ft2.hotelsabre = gh.sabre then ISNULL('Green',' ')
else ' ' end
from
fact.travel ft
left join ETL_Framework.Fact.Travel9999 ft2
on ft.OrigRecnum = ft2.RECNUM
Join ETL_Gooddata.ETL.GHCAnalysis gh
on ft2.hotelsabre = gh.sabre
where travel_type_id = 3
and
createdate >= #LoadDate
and invoicedate between #StartDate and #EndDate
--and datasourceid = #DataSourceID
and ft.datasourceid in (select d.DataSourceID from Dim.DataSource d
--left join ETL.LoadConfig c on d.DataSourceID = c.DataSourceID where case when d.DataSourceID in (2,3) then 1 else c.DataSourceID end = #DataSourceID)
left join ETL.LoadConfig c on d.DataSourceID = c.DataSourceID
where case when d.DataSourceID in (2,3) then 1
when d.DataSourceID in (11,14) then 11
else c.DataSourceID end = #DataSourceID)
When I select from the table that the above stored procedure updates, my EClassification column is only 'Green' or NULL, not 'Green' or blank.
SELECT TOP (1000) [FactTravelID]
,ft.[DataSourceID]
,[TravelTypeID]
,[TransactionID]
,[InvoiceDate]
,ft.[AHC]
,[AirMiscData1]
,[AirMiscData2]
,hotelsabre
,[EClassification]
,hotelsabre
FROM [ETL_Gooddata].[Fact].[Travel] ft
join ETL_Framework.Fact.Travel9999 ft2
on ft.OrigRecnum = ft2.recnum
where TravelTypeID = 3
and CreateDate > '2021-06-13'

Answer 1

StackOverFlow vets, still new to this. Be gentle...You're using a LEFT JOIN to ETL_Framework.Fact.Travel9999 and an INNER JOIN to ETL_Gooddata.ETL.GHCAnalysis and your ON clause is the same condition as your CASE statement evaluation. Try using a LEFT JOIN to [ETL_Gooddata].[ETL].[GHCAnalysis].
UPDATE ft
SET EClassification = CASE WHEN ft2.hotelsabre = gh.sabre THEN ISNULL('Green',' ') ELSE ' ' END
FROM [fact].[travel] ft
LEFT JOIN [ETL_Framework].[Fact].[Travel9999] ft2
ON ft.OrigRecnum = ft2.RECNUM
LEFT JOIN [ETL_Gooddata].[ETL].[GHCAnalysis] gh
ON ft2.hotelsabre = gh.sabre
WHERE travel_type_id = 3
AND createdate >= #LoadDate
AND invoicedate BETWEEN #StartDate AND #EndDate
AND ft.datasourceid IN (SELECT d.DataSourceID
FROM [Dim].[DataSource] d
LEFT JOIN [ETL].[LoadConfig] c
ON d.DataSourceID = c.DataSourceID
WHERE CASE WHEN d.DataSourceID in (2,3) THEN 1
WHEN d.DataSourceID in (11,14) THEN 11
ELSE c.DataSourceID END = #DataSourceID)