Two For each row in data table activities

[ppr (Peter Preuss)]

@Sonalk

Using for each row in data table 1, extract unique id

you can check if the first loop can be avoided when using following statement:
dtUniqueIDs = dtOrig.DefaultView.ToTable(True, {"YourIDColName"})

So the second loop can iterate over dtUniqueIDs

@Sonalk

Using Filter data table activity (pass unique id) for table 2 and use for each row in table 2 filtered records to make one record out of multiple records based on business rules.

sounds like a data grouping on ID

@Sonalk

Outside loop of table 2. Add variables in data row of table 1 columns

here the other statement should be cross-checked on possible side effects

@Sonalk

for each row in data table 1, extract unique id

when the update is placed on wrong dt1 rows, then maybe the dt1 unique ID logic is confused. We would recommend doing the first analysis by debugging and tracing the flow.

As mentioned by Raja, if possible share also some more details on sample data and implementation details with us.