Questions for Lookup transformation
Q1) How matching happens inside the lookup transformation?
Lookup transformation performs an equi-join between input data and lookup dataset. By default unmatched row is considered as an error however we can configure lookup to redirect such rows as “No match output”.
If the lookup dataset is having multiple matches it returns only the first match. In-case the lookup dataset is a cache then it raises a warning or error in case of multiple matches. Read more SSIS Interview Questions (Data Flow Transformations)