mysql - php insert into the database is not working -

i trying insert information database not working. following code:

$sql4 = "insert favorites (posted-date,posted-time,posted- datetime,journalid, by)  values ('test','test','test','test','test')"; 

try

$sql4 = "insert `favorites` (`posted-date`,`posted-time`,`posted-datetime`,`journalid`, `by`) values ('test','test','test','test','test')"; 

also check if connecting database correctly.

and have @ table , fields if of correct type , exists.