Question

i have this code which permits me to retrieve all the information in which the timestamp regarding that information is equal to another date.

Here is the code:

$information="SELECT * FROM scheda_anagrafica WHERE FROM_UNIXTIME('time_inserted','%d-%m-%Y') = '" . $giorno_selcted. "'
 "; 
$result1 = mysql_query($information) or die (mysql_error());
while( $row = mysql_fetch_array($result1)) {

    echo $row['information1'];

}

giorno_selected prints something like: 25-09-2012
What am i doing wrong here?
Thanks!

Answer 1

first of all, you should not use mysql functions on the left hand side of a operator in a where clause. this way mysql needs to read the complete table on disk to compute the value to compare with instead of optimizing the query for speed and resource usage (IO, cpu).

from your question and comments i understand, that you are querying the database for rows which have the same day as the string in your $giorno_selected represents. so you need to find all rows with timestamps between 0:00 and 23:59 on that specific day:

$giorno_timestamp_start = date_create_from_format('d-m-Y', $giorno_selected)->getTimestamp();
$giorno_timestamp_end = $giorno_timestamp_start + 86399; //add almost all seconds per day onto the start timestamp

$information="SELECT * FROM scheda_anagrafica WHERE time_inserted BETWEEN " . $giorno_timestamp_start. " AND ". $giorno_timestamp_end; 
$result1 = mysql_query($information) or die (mysql_error());
while( $row = mysql_fetch_array($result1)) {

    echo $row['information1'];

}

this works if your time_inserted column is of type integer and holds unix_timestampds.
if it is of type datetime or timestamp you need to modify the query like this:

$information="SELECT * FROM scheda_anagrafica WHERE time_inserted BETWEEN FROM_UNIXTIME(" . $giorno_timestamp_start. ") AND FROM_UNIXTIME(". $giorno_timestamp_end .")";