PHP output from SQL into a table - php

Question

I have a query that works (see query results) temporarily taken out I don't have enough points for more than two links
However, when I try to output in PHP the category name is the same for both the offeredcategory.categoryName and wantedcategory.categoryName for categoryName on output to a table (see screenshot):
I'm trying to use the alias in the query to output categoryName differently for offered and wanted.
I've also tried using $row["offeredcategory.categoryName"] and $row["wantedcategory.categoryName"] which yields an error:
Notice: Undefined index: offeredcategory.categoryName in C:\Program Files (x86)
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $connection->connect_error);
}
$sql = "SELECT customers.*, ads.*, categoriesselected.categoryselectedID, categoriesselected.offeredcategoryID, offeredcategory.categoryID, offeredcategory.categoryName, categoriesselected.wantedcategoryID, wantedcategory.categoryID, wantedcategory.categoryName
FROM customers
INNER JOIN ads ON ads.customerId = customers.customerID
INNER JOIN categoriesselected ON categoriesselected.adID = ads.adID
LEFT OUTER JOIN categories AS offeredcategory ON offeredcategory.categoryID = categoriesselected.offeredcategoryID
LEFT OUTER JOIN categories AS wantedcategory ON wantedcategory.categoryID = categoriesselected.wantedcategoryID";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
echo "<table>
<tr><th></th><th colspan=2>OFFERING</th><th colspan=2>WANTING</th><th>Location</th></tr>";
//need to prevent SQL injection using ...
while($row = $result->fetch_assoc())
{
echo
'<tr>
<td><img src="images/'.$row["fileUploadLocation"]. '" width="80" height="80" class="descImage"/></td>
<td>' ."<h6>" . $row["categoryName"]. "</h6>" . "<br>"
. $row["servicesOfferedTitle"]. '</td>
<td>' . $row["servicesOfferedDescription"]. '</td>
<td>' . $row["categoryName"]. "<br>"
. $row["servicesWantedTitle"]. '</td>
<td>' . $row["servicesWantedDescription"]. ' </td>
<td>' . $row["location"]. '</td>
</tr>';
}
echo "</table>";
} else {
echo "0 results";
}
I've now tried as suggested changing alias from joins to Select but now the joins won't work
Haven't to the $row part yet.
I've now tried as suggested changing alias from joins to Select but now the joins won't work (see screenshots):
Haven't to the $row part yet.
from manasschlcatz
Next tried 2nd suggestion but yields error:
Notice: Undefined index: offeredName in C:\Program Files (x86)
$sql = "SELECT customers.*, ads.*, categoriesselected.categoryselectedID, categoriesselected.offeredcategoryID, offeredName.categoryID, offeredName.categoryName, categoriesselected.wantedcategoryID, wantedName.categoryID, wantedName.categoryName
FROM customers
INNER JOIN ads ON ads.customerId = customers.customerID
INNER JOIN categoriesselected ON categoriesselected.adID = ads.adID
LEFT OUTER JOIN categories AS offeredName ON offeredName.categoryID = categoriesselected.offeredcategoryID
LEFT OUTER JOIN categories AS wantedName ON wantedName.categoryID = categoriesselected.wantedcategoryID" ;
$result = $conn->query($sql);
if ($result->num_rows > 0) {
echo "<table>
<tr><th></th><th colspan=2>OFFERING</th><th colspan=2>WANTING</th><th>Location</th></tr>";
//need to prevent SQL injection using ...
while($row = $result->fetch_assoc())
{
echo
'<tr>
<td><img src="images/'.$row["fileUploadLocation"]. '" width="80" height="80" class="descImage"/></td>
<td>' . $row["offeredName"]. "<br>"
. $row["servicesOfferedTitle"]. '</td>
<td>' . $row["servicesOfferedDescription"]. '</td>
<td>' . $row["wantedName"]. "<br>"
. $row["servicesWantedTitle"]. '</td>
<td>' . $row["servicesWantedDescription"]. ' </td>
<td>' . $row["location"]. '</td>
</tr>';
}

Answer 1

You have duplicate field names: offeredcategory.categoryNameand wantedcategory.categoryName will both be retrieved $row['categoryName'] so only one will show up - categoryName is ambiguous but not rejected by MySQL because the SQL statement is clear and the problem is processing the results in PHP. Simple solution is:
offeredcategory.categoryName as offeredName
wantedcategory.categoryName as wantedName
and retrieve with $row['offeredName'] or $row['wantedName'] depending on what you actually want to display.
Complete SQL becomes:
SELECT customers.*, ads.*, categoriesselected.categoryselectedID, categoriesselected.offeredcategoryID, offeredcategory.categoryID, offeredcategory.categoryName as offeredName, categoriesselected.wantedcategoryID, wantedcategory.categoryID, wantedcategory.categoryName as wantedName
FROM customers
INNER JOIN ads ON ads.customerId = customers.customerID
INNER JOIN categoriesselected ON categoriesselected.adID = ads.adID
LEFT OUTER JOIN categories AS offeredcategory ON offeredcategory.categoryID = categoriesselected.offeredcategoryID
LEFT OUTER JOIN categories AS wantedcategory ON wantedcategory.categoryID = categoriesselected.wantedcategoryID";