PHP / MYSQL：比较一列中的单元格，并覆盖另一列或表中的匹配子字符串

Question

I have a bunch of item names I want to overwrite with links that have the name in them as a substring. So I thought to put the data into columns and simply overwrite if the substring matches. However this has become harder than I thought and I can't find any solution after a lot of trying.

Item Name  |                 Link
==================================================
Ice Tea    | <a href="www.nothing.com">Spiced Rum</a>
Spiced Rum | <a href="www.nothing.com">Peaches</a>
           | <a href="www.nothing.com">Ice Tea</a>                 

And I want it to look like:

Item Name                                |                 Link
====================================================================================
<a href="www.nothing.com">Ice Tea</a>    | <a href="www.nothing.com">Spiced Rum</a>
<a href="www.nothing.com">Spiced Rum</a> | <a href="www.nothing.com">Peaches</a>
                                         | <a href="www.nothing.com">Ice Tea</a> 

First I tried doing this with some PHP string functions, but I could not figure out how to loop through the ENTIRE Link column until a match is found, for each Item Name. All I've managed to do is replace row by row.

    <?php
require_once('connectvars.php');

// Connect to the database
$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME)
or die('Error connecting to MySQL server.');
$query = "SELECT Item, Link FROM MyDB";

$data = mysqli_query($dbc, $query)
or die(mysqli_error($dbc));

$i = 1;

while ($row = mysqli_fetch_array($data, MYSQLI_ASSOC)) {

    $item = $row["Item"];
    $link = $row["Link"];

    $match = stripos($link, $item);

    if ($match !== false) {

            $query = "UPDATE Test SET Item = '$link' where ID = $i";

            if (mysqli_query($dbc, $query)) {
                echo "Record updated successfully";
            } else {
                echo "Error updating record: " . mysqli_error($dbc);
            }

        }
$i++;
}
mysqli_close($dbc);

?>

Then I tried various ways to use MySQL functions to replace a substring but I can't seem to get this to work.

SELECT column1, column2 
FROM table 
WHERE column1 LIKE CONCAT('%', column2, '%');

I could move the data to separate tables if that helps.

Answer 1

Use LOCATE mysql function which finds a first position of a substring in a string, you'll need to find Item in a Link :

UPDATE Test SET `Item` = `Link` WHERE 0 < LOCATE(`Item`, `Link`)

If you want to skip rows where Item is NULL :

UPDATE Test SET `Item` = `Link` where `Item` IS NOT NULL AND 0 < LOCATE(`Item`, `Link`)

Answer 2

I was overthinking this a little. I didn't realise I could use strpos with arrays (if you simply extract each array value). So now this will increment through Text and scan through Link until there is a match, then overwrite Text with Link.

This is just for updating a large list of extracted data, not for "live" code.

<?php
require_once('connectvars.php');

// Connect to the database
$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME)
or die('Error connecting to MySQL server.');
$query = "SELECT Text, Link FROM Items";

$data = mysqli_query($dbc, $query)
or die(mysqli_error($dbc));

$text = array();
$link = array();
$id = 1;

while ($row = mysqli_fetch_array($data)) {

    $text[] = $row["Text"];
    $link[] = $row["Link"];

}


for ($i = 0; $i < sizeof($text); $i++) {

    $string_text = $text[$i];


    for ($j = 0; $j < sizeof($link); $j++) {

        $string_link = $link[$j];

        $match = stripos($string_link, $string_text);

        if ($match !== false) {

            $link[$j] = $string_link;

            $query = "UPDATE Items SET Text = '$link[$j]' WHERE ID = '$id'";
            if (mysqli_query($dbc, $query)) {
                echo "Record updated successfully";
            } else {
                echo "Error updating record: " . mysqli_error($dbc);
            }

        }


    }
    $id++;
}

mysqli_close($dbc);

?>