php - randomly choose one data from blocks of query -

-

i have 100000 records in table. need make query reads 10 records , after 10 more records continuously until end of table. each of 10 rows groups, need pick 1 random row. possible accomplish using mysql query? need idea this. can me?

i have tried php loop doesn't work.

<?php include_once ("connection.php");  $data = mysql_query("select * trying"); $result = array();   while ($data2 = mysql_fetch_array($data)) {     array_push($result, array('no'=> $data2['no'],                       'source'=> $data2['source'],                  'destination'=> $data2['destination'])); }  $e=0;    ($a = 0; $a <= 49;) {      ($i = 0; $i <= 9; $i++,$a++) {         $rand = array();         $rand[$i] = $result[$a];       }     echo json_encode($rand[1]);  }  ?>

insted of this:

for ($a = 0; $a <= 49;) {      ($i = 0; $i <= 9; $i++,$a++) {         $rand = array();         $rand[$i] = $result[$a];       }     echo json_encode($rand[1]);  }

you can use this:

$rand = array(); $step = 10;  ($min = 0; $min <= 49; $min = $min + $step) {        $max = $min + $step;     $rand[] = $result[rand($min,$max)]; } echo json_encode($rand);

Comments

Post a Comment

Popular posts from this blog

c++ - OpenCV Error: Assertion failed <scn == 3 ::scn == 4> in unknown function, -

-
i read alot other solution still confused should mine... #include <opencv2/objdetect/objdetect.hpp> #include <opencv2/highgui/highgui.hpp> #include <opencv2/imgproc/imgproc.hpp> #include <iostream> #include <stdio.h> using namespace std; using namespace cv; int main(int argc, const char** argv) { //create cascade classifier object used face detection cascadeclassifier face_cascade; //use haarcascade_frontalface_alt.xml library face_cascade.load("haarcascade_frontalface_alt.xml"); //setup video capture device , link first capture device videocapture capturedevice; capturedevice.open(0); //setup image files used in capture process mat captureframe; mat grayscaleframe; //create window present results namedwindow("outputcapture", 1); //create loop capture , find faces while (true) { //capture new image frame capturedevice >> captureframe; ...
Read more

php - render data via PDO::FETCH_FUNC vs loop -

-
i've been using 2 methods render data. the first one: function name($id,$name){ return '<div id="'.$id.'">'.$name.'</div>'; } echo implode($pdo->query("select id,name user")->fetchall(pdo::fetch_func,'name')); the second one: $users = $pdo->query("select id,name user")->fetchall(pdo::fetch_obj); foreach($users $user){ echo name($user->id,$user->name); } i don't understand how pdo::fetch_func works. tried figure out. however, not well-documented. could please explain fetch mode? , also, 1 performs better? thank you. both methods wrong , have learn how use templates , how separate business logic presentation logic. $users = $pdo->query("select id,name user")->fetchall(pdo::fetch_obj); tpl::assign('users', $users); is code business logic part. then in template <?php foreach $users $row): ?> <div id="<?=$...
Read more

The canvas has been tainted by cross-origin data in chrome only -

-
uncaught securityerror: failed execute 'getimagedata' on 'canvasrenderingcontext2d': canvas has been tainted cross-origin data i getting above error in chrome. code(following) works fine in mozilla. have not corss domain issue. why above error in chrome? var wheel_canvas, wheel_context, can_w, can_h, wheel_grd; var large_radius = 160; var small_radius = 120; var wheel_canvas = document.getelementbyid('wheel_canvas'); var wheel_context = wheel_canvas.getcontext('2d'); var can_w = $(wheel_canvas).width(); var can_h = $(wheel_canvas).height(); var centerx = can_w / 2, centery = can_h / 2; var wheel_grd = null; test('#ff0000'); function test(hex) { $('#clrpicker').css({'left': 210, 'top': 210 }); inverted = hexbw(hex); $('#color_val_show').val(hex); current_color_hex_val_selected = hex; $('#color_val_show').css({'color':inverted,'background':hex}); fillgradient...
Read more