SSIS error: The SQL command requires a parameter named, which is not found in the parameter mapping

SSIS error message:

The SQL command requires a parameter named "@aaaa", which is not found in the parameter mapping.

Cause and Solutions:

1. The parameter is really not exists. Solution: declare it.

2. Space - " " - in the mapping pf the parameter - see the picture below. Solution: delete the space.

OUTPUT Clause for the MERGE Statements

MERGE ....

USING...

WHEN ...

WHEN ...

...

OUTPUT

   $action,

   inserted.*,

   deleted.*;