mysqli - How to fetch a row without modifying the result set? - php

Is it possible to extract a value from mysqli_result without fetching a row i.e. without modifying the result set as I need it in full later in my code?

You can also point the iterator back to the beginning. ie..
$result = $mysqli->query($query);
while($row = $result->fetch_assoc())
{
//do stuff with the result
}
//back to the start
mysqli_data_seek($result,0);
now the pointer is returned to the beginning. mysqli_data_seek

You can get all and store in an array…
$results = [];
$sql = mysqli_query($con,"SELECT * FROM WHATEVER");
while ($row = mysqli_fetch_array($sql)) {
array_push($results, $row);
}
//Now $results is fully populated

Related

MySQL SELECT Command does find one entry less

here is my problem.
function getSent($id) {
include 'dbh.php';
$data = array();
$sql = "SELECT * from message WHERE senderid='$id'";
$result = $con->query($sql);
$row = $result->fetch_assoc();
while($row = $result->fetch_assoc()) {
$data[] = $row;
}
return $data;
}
In the theory this method is picking all messages (in this case), but it always find one message less than in the db => If I drop the whole table, I will get an array with the size of 0.
How could I fix this?
Remove the first $row = $result->fetch_assoc();. You are fetching one row, then looping to fetch the rest of the data and you don't store the first fetch.
`

PHP - doesn`t show anything with mysqli_fetch_assoc in while-loop

I want to give some data from a MySQL database to a Android App via JSON.
So far i have written this php script to give me the JSON object:
$result = mysqli_query($con,"SELECT * FROM job");
$row = mysqli_fetch_assoc($result);
while($row = mysqli_fetch_assoc($result)){
$output[] = $row;
}
print(json_encode($output));
I have found out by accident that when I dont add the line "$row = mysqli_fetch_assoc($result);" before the while-loop it doesn`t return anything. But when I do add this line like in the example the JSON object doesnt contain the first element.
I believe its because of this line where $row already contains the first line.
Hopefully you can help me :)
With purpose to figure out what wrong with your query you have to do something like this:
if ($result = mysqli_query($db, $sql)) {
// Here you can see and check count of rows in your result set.
$numRows = mysqli_num_rows($result);
// ...
} else {
// Here you can see and check and understand error.
var_export(mysqli_error($db));
}
with purpose to traverse all your rows from result set you have to do:
while ($row = mysqli_fetch_assoc($result)) {
var_export($row);
}
and you must not have $row = mysqli_fetch_assoc($result) before while loop.

Selecting multiple rows in a table

I need to select multiple comments (if there are any) based on the photo_id. As I understand it you can use the WHERE clause but I'm not exactly sure how to select multiple ones and store them in some kind of array?
e.g.
$result = mysqli_query($conn,"SELECT * FROM comments WHERE photo_id='$photo1id'");
$row = $result->fetch_assoc(); // but there's more than 1 row
If for example $photo1id == 21, how do I get all the comments (2 in this case)? Some kind of while loop?
At the end of the PHP file I have this:
echo json_encode(array('photo1id'=>$photo1id));
I need to store each row in that array somehow because I need to retrieve the data in another PHP file using $.getJSON. Or perhaps there is a better solution to this.
Loop through it and generate an array -
while($row = $result->fetch_assoc()) {
$comments[] = $row;
}
After that you can send the array as json.
echo json_encode($comments);
Is there is more rows, you need to use a loop.
while ($row = $result->fetch_assoc()) {
// your code here
}
Try the code below:
//Run query
$result = mysqli_query($conn,"SELECT * FROM comments WHERE photo_id='$photo1id'");
//While there is a result, fetch it
while($row = $result->fetch_assoc()) {
//Do what you need to do with the comment
}
If you don't want to print the code straight away you can just create an array:
$x=0;
while($row = $result->fetch_assoc()) {
$comment[$x]=$row['comment'];
$x++;
}

MySQL results issue in php array

Can anybody tell me why not all the results for MySQL aren't ending up in the array?
$result = mysql_query("select * from groups order by id desc");
if ($row = $result->fetch()) {
$groups[] = $row;
}
Use while not if
while ($row = $result->fetch()) {
$groups[] = $row;
}
The code you have there does not iterate over the result set.
Try this instead.
while ($row = $result->fetch()) { 
$groups[] = $row;
}
Because fetch only fetches a row as explained in the php manual:
Fetches the next row from a result set
I'd like to suggest changing your mysql_ code for PDO
$db = new PDO("..."); // Creates the PDO object. Put the right arguments for your connection.
$statement = $db->prepare("SELECT * FROM groups ORDER BY id DESC");
$statement->execute();
while ($groups = $statement->fetch())
{
// Do whatever you want to do
}

Get rows from mysql table to php arrays

How can i get every row of a mysql table and put it in a php array? Do i need a multidimensional array for this? The purpose of all this is to display some points on a google map later on.
You need to get all the data that you want from the table. Something like this would work:
$SQLCommand = "SELECT someFieldName FROM yourTableName";
This line goes into your table and gets the data in 'someFieldName' from your table. You can add more field names where 'someFieldName' if you want to get more than one column.
$result = mysql_query($SQLCommand); // This line executes the MySQL query that you typed above
$yourArray = array(); // make a new array to hold all your data
$index = 0;
while($row = mysql_fetch_assoc($result)){ // loop to store the data in an associative array.
$yourArray[$index] = $row;
$index++;
}
The above loop goes through each row and stores it as an element in the new array you had made. Then you can do whatever you want with that info, like print it out to the screen:
echo $row[theRowYouWant][someFieldName];
So if $theRowYouWant is equal to 4, it would be the data(in this case, 'someFieldName') from the 5th row(remember, rows start at 0!).
$sql = "SELECT field1, field2, field3, .... FROM sometable";
$result = mysql_query($sql) or die(mysql_error());
$array = array();
while($row = mysql_fetch_assoc($result)) {
$array[] = $row;
}
echo $array[1]['field2']; // display field2 value from 2nd row of result set.
The other answers do work - however OP asked for all rows and if ALL fields are wanted as well it would much nicer to leave it generic instead of having to update the php when the database changes
$query="SELECT * FROM table_name";
Also to this point returning the data can be left generic too - I really like the JSON format as it will dynamically update, and can be easily extracted from any source.
while ($row = mysql_fetch_array($result, MYSQL_ASSOC))
{
echo json_encode($row);
}
You can do it without a loop. Just use the fetch_all command
$sql = 'SELECT someFieldName FROM yourTableName';
$result = $db->query($sql);
$allRows = $result->fetch_all();
HERE IS YOUR CODE, USE IT. IT IS TESTED.
$select=" YOUR SQL QUERY GOOES HERE";
$queryResult= mysql_query($select);
//DECLARE YOUR ARRAY WHERE YOU WILL KEEP YOUR RECORD SETS
$data_array=array();
//STORE ALL THE RECORD SETS IN THAT ARRAY
while ($row = mysql_fetch_array($queryResult, MYSQL_ASSOC))
{
array_push($data_array,$row);
}
mysql_free_result($queryResult);
//TEST TO SEE THE RESULT OF THE ARRAY
echo '<pre>';
print_r($data_array);
echo '</pre>';
THANKS

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