select and insert in one command

[admin]

is there anyay, for MySQL to combine this into one statment. Seems silly to have extra statment to check if the user exists already.


// check to make see if the user id exists already
$qry = \"select from table id where username=\'$username\'\";
$mysql->query($qry);

if (!mysql_affeted_rows) {
$qry = \"insert into table whatever . .\"
$mysql->query($qry);
}