在MySQL中求和多列

Question

so I have a problem trying to sum up all column values. I need to sum up 4 column values in order to echo the total. Column values can only be 1 or 0. Here's the code:

$q = $mysqli->query("SELECT SUM(0_title + 1_title + 2_title + 3_title + 4_title + 5_title) AS total from PlayerTitles");
$row1 = $q->fetch_assoc();
echo $row1['SUM(total)'];

And it does not display anything. I just need a total amount of titles. Please help, thank you.

Answer 1

您在查询中使用了“ AS total”，因此将成为数组索引：

$row1['total']