Yeah, it's a work around. Another option can be use a flag in source table like boolean 0/1 or char T/F etc. Use the flag to determine new rows. But...

Fetch PK from source. Use PK as we need a distinct value for each row for Lookup in the destination table. In Lookup task, define ur destination and use PK...

You can use lookup in dataflow task in SSIS. After lookup, use conditional split for either updation/insertion in destination table. But in order to achieve this, you should have a...