For efficiency, SAP Sybase IQ passes off as much of the statement as possible to the remote server. Often, this is the complete statement originally given to SAP Sybase IQ.
SAP Sybase IQ hands off the complete statement when:
Every table in the statement resides on the same remote server.
The remote server can process all of the syntax in the statement.
In rare conditions, it may actually be more efficient to let SAP Sybase IQ do some of the work instead of the remote server doing it. For example, SAP Sybase IQ may have a better sorting algorithm. In this case, you may consider altering the capabilities of a remote server using the ALTER SERVER statement.