for the second question, use the SQL 'BETWEEN' operator:

  SELECT * FROM yourtable WHERE datcol BETWEEN '2005-01-25' AND '2005-
+07-31'
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As for the primary question, look at the docs for Win32::ODBC. The ->Sql( SQL_STRING ) method Executes the SQL command SQL_STRING on the current connection. Returns ? on success, or an error number on failure. To get the data, you'll need to use the FetchRow method. This should help to get started and to see the structure returned:

my $rc = $DB->sql("SELECT SUM(Size_Byte) FROM Files_U WHERE Type ='doc
+'");
die "ERROR: $rc" if $rc;
use Data::Dumper;
while( my $row = $DB->FetchRow ){
  warn Dumper $row;
}
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