I'm doing sth like this:
$q3 = $conn3->prepare("SELECT...");
$q3->bindParam(':param1', $param1);
$q3->execute();
$check3 = $q3->fetchAll(PDO::FETCH_ASSOC);
if (!empty($check3)){
$arr = array();
while($row = $q3->fetch(PDO::FETCH_ASSOC)) {
$arr[] = $row;
}
}
but I don't see the data in arr[] later on. What exactly am I doing wrong here? Is there a better way to fetch the data from mysql to an array in php?
fetch() returns the next row in the set. fetchAll() will fetch all the (remaining) rows and move the pointer to the last row, therefore fetch() after fetchAll() will not return anything because there will not be a next row in the set.
You need one or the other. To take advantage of fetchAll you could do:
$check3 = $q3->fetchAll(PDO::FETCH_ASSOC);
foreach ($check3 as $row) {
}
or just use fetch without fetchAll:
while ($row = $q3->fetch(PDO::FETCH_ASSOC)) {
}
Your code, as is, makes the fetch() useless. You could just do:
$arr = $q3->fetchAll(PDO::FETCH_ASSOC);
Which is equivalent to:
$arr = array();
while($row = $q3->fetch(PDO::FETCH_ASSOC)) {
$arr[] = $row;
}
}
Related
$result = mysql_query($strSql);
foreach($bestmatch_array as $restaurant)
{
while($row = mysql_fetch_array($result))
{
if($restaurant == $row[0])
{
$value = $row[1];
}
}
}
What I am trying to do is sort the result of array formed by query according to the values stored in $bestmatch array.
I don't know what I am doing wrong but the 4th line just seems to run once. Please help guys. Thanx in advance.
php mysql_fetch_array() not working as expected
Your expectation is not right.
foreach($bestmatch_array as $restaurant)
{
// This loop will only run for first iteration of your foreach.
while($row = mysql_fetch_array($result))
{
}
// everything has been fetched by now.
}
That is a logically incorrect sequence.
You expect your inner loop to be called over and over again as many times as you have the outer loop run but record fetch does not work like that. For outer loop's first run all the rows in $result will be fetched and since you do not reset the counter after your while loop that means after the first run there will be no more rows for the next run.
Solution? Fetch the row from mysql first then use a simple in_array call to check whether that restaurant is there in your array.
$result = mysql_query($strSql);
while($row = mysql_fetch_array($result))
{
$name=$row[0];
if(in_array($name,$bestmatch_array))
$value=$name;
}
Store the results of the query in the array first:
$result = mysql_query($strSql);
$results_row = array();
while($row = mysql_fetch_array($result))
{
$results_row[] = array($row[0],$row[1]);
}
foreach($bestmatch_array as $restaurant)
{
foreach ($results_row as $key => $value)
{
if($restaurant == $results_row[$key][0])
{
$value = $results_row[$key][1];
}
}
}
These are my two methods for querying a database.
This is my first method that saves all the results in an array. Then i use a foreach loop to loop through the array.
public function query($query) {
$rows = array();
if ($result = $this->mysqli->query($query)) {
if($result->num_rows > 1) {
while ($item = $result->fetch_assoc()) {
$rows[] = $item;
}
//jo else sepse nxjerr error kur ska asnje row i ben fetch kur ska row.
} else if($result->num_rows == 1) {
$rows = $result->fetch_assoc();
}
return $rows;
} else {
echo "error";
}
}
Then to output I use:
$run_query = $db->query($query);
foreach ((array)$runk_query as $data) {
....
This is my second method:
$query = $db->query("SELECT * FROM ...");
while($run_query = mysqli_fetch_array($query)) {
//OUTPUT data.
....
}
I notice that in many cases I need to output the results so I think using the first method is bad because I use once the while loop and then I use again a foreach loop so the work is done twice but the second way is not very OOP.
Can anyone suggest me the best method of this or if possible another better method?
You can likely replace you entire first function with a call to mysqli_fetch_all() instead of iterating through each record with fetch_assoc(). This way you don't have to build your array result by result.
You can then run through all the results with your second foreach as per usual.
See: http://www.php.net//manual/en/mysqli-result.fetch-all.php
Alternatively if you were using PDO you could use fetchAll()
See: http://www.php.net/manual/en/pdostatement.fetchall.php
I can't seem to figure out how this loop works in PHP:
$people = array();
while($row = $result->fetch_assoc())
$people[] = $row;
It seems as though the loop would just keep going, infinitely. But, it doesn't How exactly does this work? Can someone explain it to me step-by-step? I'm guessing that the while loop could also be written like this:
while(($row = $result->fetch_assoc()) == true)
The fetch_assoc fetches one result row at a time and stores it in $row. Since this is in a loop, you are fetching until you run out of rows
In the loop you are essentially pushing the $row value into a $people array
Your code:
$people = array();
while($row = $result->fetch_assoc())
$people[] = $row;
Example how its works (MySQL):
$people = array();
$result = mysql_query($query);
$rows_count = mysql_num_rows($result);
for ($i = $rows_count - 1; $i >= 0; $i--) {
mysql_data_seek($result, $i);
$people[] = mysql_fetch_assoc($result);
}
How U see first option is more compact.
fetch_assoc will return false either upon an error or when the cursor for the fetch hits the end of all the rows and no more rows can be fetched, so it will return false.
Every time you fetch for the query, a cursor keeps track of the last returned row and will continue to keep track ultimately till you finish reading all rows.
Edit: Sorry I was thinking about PDO and not mysqli, however it should be about the same thing.
I am making a mysql query . I want to add result to an array. suppose I am selecting all user from user table. I want to get everyones name. if the row=5 i want to save every name according to the row index.
if (mysql_num_rows($query) > 0)
{
$row = mysql_fetch_array($query);
//echo ($row);
$num=mysql_num_rows($query);
echo ($num);
for ($i=1; $i<=$num;$i++){
//here I want to save all name to an array.
}
Please help.
You might be looking for something like this:
$rows = array();
// while there are more records, add them to `$rows`
while($row = mysql_fetch_assoc($result)) {
$rows []= $row;
}
Note that mysql_fetch_assoc() will just return false if there are no (more) records in the result set. So you don't need the call to mysql_num_rows()
$num = mysql_num_rows($query);
if($num > 0)
{
while($row = mysql_fetch_array($query)
{
$names[] = $row['name'];
}
}
That will create an array called $names which you can loop through later. Also, it's a good time to look into mysqli_* functions, or PDO.
I have this sample query:
$STH = $DBH->query("SELECT id FROM table");
I want to get the first row and then loop and display all rows. So I use the following to get the first row:
$STH->setFetchMode(PDO::FETCH_ASSOC);
$first_row = $STH->fetch();
$first_row = $first_row['id'];
I use while loop to display all rows again:
while ($list = $STH->fetch()) {
$id = $list['id'];
echo $id;
}
Now the while skips the first row and I want it to be displayed. Is there an equivalent to mysql_data_seek to reset the pointer again to the first row? I know fetchall can be used but it's bad on memory and wasteful. I could also run the query and limit to 1 but this is not recommended as I have a query that joins multiple tables and would be very slow. Is there any other solution?
Thanks
I take that back looks like you can use the cursor orientation contants to select the result... sample code coming... I havent tried this so you may need to play a bit. This is also based on the assumption that a PDO::FETCH_ORI_FIRST acts like a data_seek and leaves the cursor on the first position as opposed to returning it to whatever it was before.
$stmt = $pdo->prepare('SELECT id FROM table', array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL));
$stmt->execute();
$first = $pdo->fetch(PDO::FETCH_ASSOC, PDO::FETCH_ORI_FIRST);
$first_row = $first['id'];
// other stuff
// first iteration we rewind to the first record;
$cursor = PDO::FETCH_ORI_FIRST;
while (false !== ($row = $stmt->fetch(PDO::FETCH_ASSOC, $cursor))) {
$id = $row['id'];
// successive iterations we hit the "next" record
$cursor = PDO::FETCH_ORI_NEXT;
echo $id;
}
I dont think you can rewind a statement... Assuming these blocks arent seprated by a bunch of intermediary logic id just do it in the loop.
$STH->setFetchMode(PDO::FETCH_COLUMN); // no need to pull an array
$count = 0;
while ($id = $STH->fetch()) {
if($count === 0) {
$first_row = $id;
}
echo $id;
$count++;
}
Could you just use a do...while loop instead?
$STH->setFetchMode(PDO::FETCH_ASSOC);
$list = $STH->fetch();
$first_id = $list['id'];
do {
$id = $list['id'];
echo $id;
} while ($list = $STH->fetch());
You can fetch all the result, and then just act on it as an array. So, for instance, you could shift the first result off the front, and then loop over any additional rows:
<?php
$sql = "YOUR QUERY";
$stmt = $pdo->prepare($sql);
$stmt->execute();
$rows = $stmt->fetchAll(PDO::FETCH_ASSOC);
// get first row
$firstRow = array_shift($rows);
// loop over remaining rows
foreach ($rows as $row) {
// do something
}