Following -

http://blogs.msdn.com/sqlservercompact/rss.xml

I thought I would build a generic Compact Framework method that would determine if we have any rows to send back to Sql Sever.   This should save lots of those unnecessary sync's and hence GPRS/3G charges.

I came up with the following code snippet.

public bool AnyRowsToUpload(string tablename)
{
StringBuilder sbsql = new StringBuilder();
sbsql.Append("SELECT MAX(__sysIG),MAX(__sysCG) ");
sbsql.Append("FROM ");
sbsql.Append(tablename + " ");
sbsql.Append("UNION ALL ");
sbsql.Append("SELECT LastUploadedGen,SentGen80 ");
sbsql.Append("FROM ");
sbsql.Append("__sysMergeSubscriptions");

SqlCeDataReader rdr = Sql(sbsql.ToString());   // < helper function to just execute the SQL, search my blog for source
int maxig = 0;
int maxcg = 0;
int lastuploadedgen = 0;
int sentgen80 = 0;
if (rdr != null)
{
if (rdr.Read())
{
maxig = CoreDb.DbToInt(rdr[0]); // < helper function to just quickly turn reader value to int, seach my blog for source
maxcg = CoreDb.DbToInt(rdr[1]);
rdr.Read();
lastuploadedgen = CoreDb.DbToInt(rdr[0]);
sentgen80 = CoreDb.DbToInt(rdr[1]);
}
rdr.Dispose();
rdr.Close();
}
// for SQL Server 2005, uncomment the below
return maxig > lastuploadedgen || maxcg > lastuploadedgen;
// for SQL Server 2000, uncomment the below
// return maxig > sentgen80 || maxcg > sentgen80;
}

I'm particularly pleased with this (excuse my lack of modesty), because the whole thing is executed within a single call to SQL Compact.