如何对 mysql 中的所有结果求和

Question

这是我获取所有权重的查询。:

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

我得到这样的结果：

weightage
10
20
50

我想计算所有这些结果的总和，我该怎么做..?

Answer 1

试试这个：

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

Answer 2

或简称：

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

Answer 3

尝试：

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

see example here

Answer 4

您可以使用 sum() mysql 函数来计算列的总和

你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();

如何对 mysql 中的所有结果求和

How to SUM all results in mysql

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