如何在mysql中汇总所有结果

Question

这是我的查询以获得所有权重。：

$sumQuery = $conn->query("SELECT weightage FROM  r_job_skill WHERE id_job = ".$jobID." AND gdskill = 1");

我得到的结果如下：

weightage
10
20
50

我想计算所有这些结果的总和我该怎么做...？

Answer 1

或简短：

SELECT SUM(weightage) 
FROM r_job_skill 
WHERE id_job = ".$jobID." 
AND gdskill = 1;

Answer 2

您可以使用sum() mysql函数计算列的总和

您的代码看起来像这样

$sumQuery = $conn->query("SELECT sum(weightage) as total FROM  r_job_skill WHERE id_job = ".$jobID." AND gdskill = 1");
if ($sumQuery->num_rows > 0) {
while($row = $sumQuery->fetch_assoc()) {
        echo "Total: " . $row["total"];
    }
} else {
    echo "0 results";
}
$conn->close();

Answer 3

尝试：

{{1}}

see example here

Answer 4

试试这个：

SELECT SUM(weightage) FROM (SELECT weightage FROM  r_job_skill WHERE id_job = ".$jobID." AND gdskill = 1");