php - Output changes in DB data -

i have database data.

for example:

time    type 1:00    123 2:00    123 3:00    123 4:00    123 5:00    113 6:00    113 7:00    113 8:00    113 9:00    334 10:00   334 11:00   334 12:00   123 

and have output db so:

at 5:00 type changed 123 113 @ 9:00 type changed 113 334 @ 12:00 type changed 334 123 

i've tried via group by, outputted different values, ok, when there same date types, outputted first change, because grouped one, of course...

could me, please?

don't forget mark answer "solved" if solves problem.

<?php $servername = "localhost"; $username = "username"; $password = "password"; $dbname = "mydb";  // create connection $conn = new mysqli($servername, $username, $password, $dbname); // check connection if ($conn->connect_error) {         die("connection failed: " . $conn->connect_error);         }   $sql = "select time, type mytable"; $result = $conn->query($sql);  // declare 4 variables store time , type can compare previous. $time1 = ""; $type1 = ""; $time2 = ""; $type2 = "";  if ($result->num_rows > 0) {     // output data of each row     while($row = $result->fetch_assoc()) {         $time2 = $row["time"];         $type2 = $row["type"];         if ($type2 == $type1) {             $time1 = $time2;             $type1 = $type2;             }         else {             echo "at $tim2 type changed $type1 $type2";             $time1 = $time2;             $type1 = $type2;             }         }     } else {     echo "0 results";     } $conn->close(); ?> 

you can shorten code loop , write this:

    while($row = $result->fetch_assoc()) {         $time2 = $row["time"];         $type2 = $row["type"];         if ($type2 != $type1) {             echo "at $tim2 type changed $type1 $type2";             }         $time1 = $time2;         $type1 = $type2;         } 

to exclude first result when loop starts, write this:

    while($row = $result->fetch_assoc()) {         $time2 = $row["time"];         $type2 = $row["type"];         if ($type2 != $type1 && $type1 != "") {             echo "at $tim2 type changed $type1 $type2";             }         $time1 = $time2;         $type1 = $type2;         }