Question

I’m working on an integration project and have created a batchlog table where I store which combinations have been exported already and then check new data against that batchlog table. It worked pretty well as long as I mostly just stored one ID in batchlog table, let’s say Customer ID and then selected new rows from Customer table like this:

SELECT * 
FROM Customer 
WHERE CusId NOT IN (SELECT CusID FROM IntegrationBatchlog)

However, now the solution is more complex and same row from Customer table will be exported several times in combination with other data so now I have couple of separate stored procedures and more columns in IntegrationBatchlog table (CusID, OrdertypeID and PaymentMethod) and join clauses in my select so now it’s more like.

SELECT * FROM Customer c
JOIN....
JOIN...
JOIN...
WHERE there is not a row with that CusID AND OrderTypeID AND PaymentMethod in batchlog table yet.

So here I should check whether or not this exact combination has already been exported but how do you do that when you have like three several ID columns in batchlog table and you want to exclude those rows where all the three ID’s are already present in same row in batchlog table?

Answer 1

One way is to do a LEFT JOIN to the IntegrationBatchLog table and only insert rows that aren’t present.

select *
from Customer c
LEFT OUTER JOIN IntegrationBatchLog i
  on c.CusId = i.CusId 
     and c.OrderTypeID = i.OrderTypeID 
     and c.PaymentMethod = i.PaymentMethod
where
  i.CusId is null