php - Mysql为变量赋值并回显它

Question

我有这段代码，用于存储 table_2013 列总计的总和并将其存储到 $total2013。现在我想回显总和，并且还想回显 total2013 的总和加上 total2014 的总和，而不是打印我得到的总和

"Resource id #4"

            $t2013 ="SELECT SUM(total) FROM table_2013";
            $total2013 = (mysql_fetch_assoc($t2013));

            $t2014 ="SELECT SUM(total) FROM table_2014";
            $total2014 = (mysql_fetch_assoc($t2014));

            echo "$total2013";
            echo "$total2014";

            echo "$total2013 + $total2014";

Answer 1

您没有执行查询。执行它们 -

$t2013 ="SELECT SUM(total) FROM table_2013";
$total2013 = (mysql_fetch_assoc(mysql_query($t2013)));

$t2014 ="SELECT SUM(total) FROM table_2014";
$total2014 = (mysql_fetch_assoc(mysql_query($t2014)));

您还需要提供列名称 -

echo $total2013['SUM(total)'] + $total2014['SUM(total)'];