Automatically create entries in database table (php/mysql)

here is my suggestion,create one file that will store the last date of the script run,suppose today(2013-01-11) you have run that script than it will store simply 2013-01-11 in that file,if you run it again tomorrow it will store tomorrow's date 2013-01-12.

we will use this date to create query and reduce our processing time.

date stored in file is our $minDate,

find out max date from db using query say it is $maxDate,

query:Select Date,Spent from table Where date('Date')>$minDate;

Store result in a array $dateArray

create one date array using period between $minDate and $maxDate

$starting_date = new DateTime($minDate." 00:00");
$ending_date = new DateTime($maxDate." 23:59:59");


$interval = new DateInterval('P1D');
$period = new  DatePeriod($starting_date , $interval, $ending_date);
foreach ($period as $date) {
  $curDate=$date->format('Y-m-d');
  if(!in_array($curDate,$dateArray)){
     //insert new row with $curDate
  }
}
update lastProcessedDate in your file

I would approach this like this: Create a cronjob which runs your PHP script in the early morning hours (say 2am or so). The script will take the current date minus 1 (yesterday) and use a select query to the database. If it does not find an entry, it will create one. When you have it running every day, you will make sure, that there is always an entry of yesterday.

You could create a stored procedure and schedule it to run nightly. Something like create cursor to loop through the table, order by the Date column, then check the previous record to see how many days are missing, if more than 1, insert individually.