您好,我正在查询我的数据库,以便我可以比较每两行。 ex 1和2,然后是2和3,然后是3和4.依此类推。但它只比较前两行。有任何想法吗?这是我的代码:
$result = mysql_query("SELECT *FROM attendance ORDER BY pid ASC") or die(mysql_error());
// check for empty result
if (mysql_num_rows($result) > 0) {
// $response["nominees"] = array();
while ($row = mysql_fetch_array($result)) {
// temp user array
$prev_sid = $row["sid"];
$prev_pid = $row["pid"];
$row2 = mysql_fetch_array($result);
if($row2["pid"] == $prev_pid){
if(($row2["sid"] - $prev_sid) == 1){
$attended_elec = mysql_query("SELECT pid FROM election_attendance where election_id = '$election_id'");
if(mysql_num_rows($attended_elec) > 0){
$not_officer = mysql_query("SELECT usertype FROM users WHERE pid = '$prev_pid'");
if(mysql_result($not_officer, 0) == "member"){
// echo "PID" . $prev_pid;
// $nominee["pid"] = $row2["pid"];
$user_details = mysql_query("SELECT *FROM users WHERE pid = '$prev_pid'");
if(mysql_num_rows($user_details) > 0){
$response["nominees"] = array();
while ($row3 = mysql_fetch_array($user_details)) {
$nominee = array();
$nominee["pid"] = $row3["pid"];
$nominee["firstname"] = $row3["firstname"];
$nominee["lastname"] = $row3["lastname"];
$nominee["gender"] = $row3["gender"];
$nominee["contact"] = $row3["contact"];
$nominee["email"] = $row3["email"];
$nominee["address"] = $row3["address"];
$nominee["institution"] = $row3["institution"];
$nominee["points"] = $row3["points"];
$nominee["usertype"] = $row3["usertype"];
// push single product into final response array
array_push($response["nominees"], $nominee);
}
}
}
}
}
}
}
// success
$response["success"] = 1;
// echoing JSON response
echo json_encode($response);
} else {
// no products found
$response["success"] = 0;
$response["message"] = "There is no candidate yet from the records.";
// echo no users JSON
echo json_encode($response);
}
提前感谢,祝你有愉快的一天
答案 0 :(得分:1)
在while()处遇到问题,你正在取第一行,并且是正确的。 然后,在它内部你获取第二个,这是你想要的,但是当迭代重复时,while将获取第3个,而内部第4个,所以你在第2个和第3个之间丢失了比较。
// fetch data from DB
$results = "...";
if (mysql_num_rows($result) < 1)
{
// no products found tell your users
return;
}
// lets make some variables to walk through the list
$previous = mysql_fetch_array($results);
$actual = null;
// and now lets walk through the list
while($actual = mysql_fetch_array($results))
{
// execute your logic here
// than at the end move the actual row to become the previous
$previous = $actual;
}
注意您不应该使用 mysql _ *方法,这些方法已被弃用。你可以使用兄弟 mysqli _ *或PDO
答案 1 :(得分:0)
我会做这样的事情吗?但几乎可以肯定,资源密集程度较低。
$x = 0;
$y = 1;
$total = mysql_num_rows(mysql_query("SELECT * FROM `the_place`");
while ($x < $total AND $y < total){
$query1 = "SELECT * FROM `the_place` LIMIT $x,1";
$query2 = "SELECT * FROM `the_place` LIMIT $y,1";
$row1 = mysql_fetch_array(mysql_query($query1);
$row2 = mysql_fetch_array(mysql_query($query2);
// Do comparison here
if ($row1 == $row2){
// etc
}
$x = $x++;
$y = $y++;
}