[英]Php Mysql Display sum of 2 columns in html
我想在html中顯示“ Vendido -Pagado”(表的2列)的結果,但是以下代碼不起作用,任何線索為何?
<?php
//connect to db
include '../connect.php';
$saldo = "SELECT Vendido-Pagado AS Saldo FROM Cooks WHERE Mail = '$email'";
$resultsaldo = mysqli_query($conn, $saldo);
if (mysqli_num_rows($resultsaldo) > 0) {
// output data of each row
while($row3 = mysqli_fetch_assoc($resultsaldo) {
echo '<a class="w-nav-link navlink right" href="../misaldo.php">Saldo: '
.$row3['Saldo']. "</a>";
}} else { echo "There was an error fetching the total";}
mysqli_close($conn);
?>
對於MYSQL查詢中的SUM,可以使用MYSQL SUM聚合函數
$saldo = "SELECT (SUM(Vendido) + SUM(Pagado)) AS Saldo FROM Cooks WHERE Mail = '$email'";
要么
我使用$row3['col1']
和$row3['col2']
來顯示如何總結兩列,不要忘記更改列的名稱
col1
, col2
。
while($row3 = mysqli_fetch_assoc($resultsaldo) {
echo "Sum of two columns : ".($row3['col1'] + $row3['col2']);
}
注意:如果您使用的是mysqli
也最好使用mysqli准備好的語句。
您可以直接使用sql查詢。
改變這個
SELECT Vendido-Pagado AS Saldo FROM Cooks WHERE Mail = '$email'
至
SELECT CONCAT( Vendido, '-', Pagado ) AS Saldo FROM Cooks WHERE Mail = '$email'
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