在PHP中将3列与MySQL串联

Question

I have an Android app that will POST the category variable to my PHP. In my PHP i wand to find the category (column) the buyer is interested in and then in that row concatenate the 3 other columns from that same row. Then save that into a variable which i will echo out.

i realize there are multiple products listed in the same category but that is a different question.

PHP code:

<?php

$conn = mysqli_connect("phpmyadmin.cvw71h2krjrb.us-east-1.rds.amazonaws.com", "phpmyadmin", "phpmyadmin", "Products");

$Category = $_POST["Category"];

//$sql_query = "select Product_Category from Products where Product_Category     like '$Category'";

$sql_query = "select concat(Product_Owner_Email,'_',Product_Name,'_',     Product_Key_Code) as productkeyword from table where <Product_Category like     '$Category'>";

$result = mysqli_query($conn, $sql_query);

if(mysqli_num_rows($result) > 0 ){

$row = mysqli_fetch_assoc($result);
$Product_Owner_Email =  $row['Product_Owner_Email'];
$Product_Name =  $row['Product_Name'];
$Product_Key_Code =  $row['Product_Key_Code'];

}

mysqli_close($conn);

echo $ProductKeyWord;
?>

How can i concatenate 3 columns with MySQL in PHP?

also

On my app the echo back is ""

...................................................................... ANSWER BELOW ............................................................

<?php

 ini_set('display_errors',1); ini_set('display_startup_errors',1);   error_reporting(E_ALL);//This code is used so if i test the PHP in the browser itll tell me any errors or warnings!! 

 $conn = mysqli_connect("XXXX", "XXXX", "XXXX", "Products");

 $Category = $_POST["Category"];

 $sql = "SELECT Product_Owner_Email, Product_Name, Product_Key_Code FROM     Product_Details WHERE Product_Category LIKE '$Category'
 LIMIT 0 , 30";
 $result = $conn->query($sql);

 if ($result->num_rows > 0) {
     // output data of each row
     while($row = $result->fetch_assoc()) {
         echo $row["Product_Owner_Email"]. "_" . $row["Product_Name"]. "_" .    $row["Product_Key_Code"] . " ";
     }
 } else {
     echo "0 results";
 }
 $conn->close();
 ?>

the answer actually returns every "product" in the $Category

Answer 1

You can use the below query:

select concat(Product_Owner_Email,'_',Product_Name,'_', Product_Key_Code) as productkeyword from table where <where condition>

I have updated your code, now try this.

$conn = mysqli_connect("phpmyadmin.cvw71h2krjrb.us-east-1.rds.amazonaws.com", "phpmyadmin", "phpmyadmin", "Products");

$Category = $_POST["Category"];

//$sql_query = "select Product_Category from Products where Product_Category     like '$Category'";

$sql_query = "select Product_Owner_Email,Product_Name,concat(Product_Owner_Email,'_',Product_Name,'_',Product_Key_Code) as productkeyword from Products where Product_Category  like '".$Category."'";

$result = mysqli_query($conn, $sql_query);

if(mysqli_num_rows($result) > 0 ){

$row = mysqli_fetch_assoc($result);
$Product_Owner_Email =  $row['Product_Owner_Email'];
$Product_Name =  $row['Product_Name'];
$Product_Key_Code =  $row['productkeyword'];

}

mysqli_close($conn);

echo $Product_Key_Code;
?>