Following pseudo-code is essentially you need to do
#Make connection
$Connection = DBI->connect(server, username, password);
#Create empty csv file
open(MyFile, ">test.csv");
#Make a query
$QueryString = qq{select * from database-table};
$Query = $Connection->prepare($QueryString);
$Query->execute();
while(@Array = $Query->fetchrow_array())
{
print MyFile, $Array[0], $Array[1];
}