Some Date::Manip (mainly used for day of the week type stuff):

  $companystartdate = &ParseDate("today"); # returns 2000082415:40:44 format
  $companystartdate =~ s/^(....)(..).+/$1-$2-01/; # build 2000-08-01

Some SQL:

my $statement = "select * from charges where 
   (UserId='$userhash{'UserId'}' AND 
   (Date BETWEEN '$start' AND 
         DATE_ADD('$start', interval 6 day)
    )
   ) order by ClientGroupId,ClientId,Date";

and

my $monthstart = substr($sqlstartdate,0,8) . "01"; # 2000-08-01
my $monthend = "DATE_SUB(
  ( DATE_ADD('$monthstart',interval 1 month) ),
             Interval 1 day)"; # 1mo less 1dy. too many parens?
my $statement="select sum(Hours) from charges where 
  (UserId='$userhash{'UserId'}'
   and ClientId='$client' 
   and FeeType='$fee'
   and Date between '$monthstart' and $monthend
   ) group by UserId";