Query Activity system error in Automation Studio

Question

Why am I getting a system error with this Query Activity in Automation Studio?

Select 
  o.AccountID
, o.JobID
, o.SubscriberKey
, o.EventDate
, o.isUnique
, o‌​.Domain
, o.Subscriber‌​ID
, o.OYBAccountID
, o.‌​ListID
, o.BatchID,
s.T‌​riggererSendDefiniti‌​onObjectID 
from _Open as o 
where DATEDIFF(hour, o.EventDate, GETDATE()) <= 0

Answer 1

Typically if Query Activities fail, it's one of these 6 things:

1. Primary key violation -- your query results in duplicate rows not allowed by the primary key
2. Inserting a null value into a non-nullable field
3. Inserting a value too long for the field (truncation)
4. Timeout -- if your query doesn't complete within the 30-minute timeout window, it'll error out.
5. Your target Data Extension no longer exists
6. Data type conversion -- trying to insert a $12.34 string into a Decimal field

SFMC Support can tell you the exact error from the server log.

I've previously written about my go-to methods for troubleshooting errors like these.

Answer 2

This is a common error when the structure of the target data extension does not match the incoming data.

You can work around this by checking your Text/Date/Number data types, and making all fields NULLABLE.

If you still have problems, double check the source data format matches the Data extension you've made: Data View: Open