I have the following code
fromProviderNPI as ProviderNPINumber,
(txt, codepage is 1252, embedded labels, delimiter is ',', msq)
Where referralType ='O'
Left Join (ECW_Temp)
From Source p
p.DeletedBy IS NULL
p.ProviderNPINumber IS NOT NULL
When I look at the resulting table "ECW_Temp" I am seeing only null value for
ProviderType and ProviderTypeCategory. I have manually checked and I know there are ProviderNPINumber's that match to each other from both sources.
Don't JOIN but keep the tables linked (an outer JOIN also could do the job)
Then create a table chart with fields fromProviderName, ProviderNPINumber, ProviderType and ProviderTypeCategory.
This table should allow you check the field values of your key in both tables and may give us a hint why the match doesn't work.