How do I update mysql database WHERE value = value from PHP array? - php

Question

I am trying to use the keys of an array as values to update a column in my database. The column in question is the sort order for the rows.
Lets say the sort column values for each row are 1, 3, 5, 8, 9, 10, 12.
When the code is executed this is to be updated to read 1, 2, 3, 4, 5, 6, 7.
My code below does what I am trying to achieve when I echo the values however I am having a problem with the update query.
$sql = "SELECT asset, sort FROM portfolio ORDER BY sort ASC";
$query = mysqli_query($conn, $sql);
$i = 0;
while ($row = mysqli_fetch_assoc($query)){
$asset[$i] = $row['asset'];
$sort[$i] = $row['sort'];
$new_sort = $i+1;
$assets = implode(',', $asset);
$update_sql = "UPDATE portfolio SET sort='$new_sort' WHERE asset IN ('$assets')";
mysqli_query($conn, $update_sql);
$i++;
}
Using the following only the first row is being updated:
$assets = implode(',', $asset);
Using the following all rows are being updated, however they are all being set to the last value, in this example it would be 7.
$assets = join("','",$asset);
UPDATE: $assets is a string, an example would be google,yahoo,apple etc..
Any ideas where I am going wrong?
Many Thanks.

Answer 1

You are setting the new_sort for every asset every time you loop through.
First loop:
$assets[0] => "asset1"
$new_sort => 2
Update new_sort = 2 where asset in $assets. (So only asset1 will be updated.)
Second loop:
$assets[0] => "asset1"
[1] => "asset2"
$new_sort => 3
Update new_sort = 3 where asset in $assets (So asset1 and asset 2 will be updated)
This will result into always setting the new_sort for every asset to the latest new_sort value;
The code for your output could be:
while ($row = mysqli_fetch_assoc($query)){
$new_sort = $i+1;
$update_sql = "UPDATE portfolio SET sort='" . $new_sort . "' WHERE asset='" . $row['asset'] . "';";
mysqli_query($conn, $update_sql);
$i++;
}

Answer 2

This the solution for your desired output.
$sql = "SELECT asset, sort FROM portfolio ORDER BY sort ASC";
$query = mysqli_query($conn, $sql);
$i = 0;
while ($row = mysqli_fetch_assoc($query)){
$asset[$i] = $row['asset'];
$sort[$i] = $row['sort'];
$new_sort = $i+1;
$assets = implode(',', $asset);
$update_sql = "UPDATE portfolio SET sort='$new_sort' WHERE asset like '".$row['asset']."'";
mysqli_query($conn, $update_sql);
$i++;
}

Answer 3

First of all you need to move your UPDATE query outside the while loop than you can use like that:
$assets = implode("','", $asset); // split $asset in comma and single quote.
$update_sql = "UPDATE portfolio SET sort='$new_sort' WHERE asset IN ('$assets')";
You are already store your values in an array $asset[$i] = $row['asset']; so no need to use query inside the while loop.
In your code, you are update the last value of $i in sort column.
The other solution is very simple, update single record as:
<?php
$sql = "SELECT asset, sort FROM portfolio ORDER BY sort ASC";
$query = mysqli_query($conn, $sql);
$i = 0;
while ($row = mysqli_fetch_assoc($query)){
$new_sort = $i+1;
$assets = $row['asset'];
$update_sql = "UPDATE portfolio SET sort = '$new_sort' WHERE asset = '$assets'";
mysqli_query($conn, $update_sql);
$i++;
}
?>