如何将mysql表中的两个值放入一个变量中？

我的查询是这样的：

$pdo = $db->prepare('SELECT *,
s.name as name,
s.firstname as firstname,
FROM projects pj
LEFT JOIN school s ON pj.teacher=s.id 
WHERE project_id = :project_id ');  
$pdo->execute(array('project_id' => $project_id));
while ($row = $pdo->fetch(PDO::FETCH_ASSOC)) {
    echo $row["firstname"].' '.$row["name"];
}

我想知道是否有办法将两个值放入一个变量中。我想象这样的情况：

$pdo = $db->prepare('SELECT *,
s.firstname.''.name as teacher,
FROM projects pj
LEFT JOIN school s ON pj.teacher=s.id 
WHERE project_id = :project_id ');  
$pdo->execute(array('project_id' => $project_id));
while ($row = $pdo->fetch(PDO::FETCH_ASSOC)) {
    echo $row["teacher"];
}

---

如果您使用的是mysql，您可以

concat

连接：

SELECT *,
CONCAT(s.firstname, s.name) as teacher,
FROM projects pj
LEFT JOIN school s ON pj.teacher=s.id 
WHERE project_id = :project_id 

---

如果您使用的是mysql，您可以

concat

连接：

SELECT *,
CONCAT(s.firstname, s.name) as teacher,
FROM projects pj
LEFT JOIN school s ON pj.teacher=s.id 
WHERE project_id = :project_id 

---

您可以使用MySQL的CONCAT：

$pdo = $db->prepare('SELECT *,
CONCAT(s.firstname, ' ', s.name) AS teacher
FROM projects pj
LEFT JOIN school s ON pj.teacher=s.id 
WHERE project_id = :project_id ');  

$pdo->execute(array('project_id' => $project_id));
while ($row = $pdo->fetch(PDO::FETCH_ASSOC)) {
    echo $row["teacher"];
}

---

您可以使用MySQL的CONCAT：

$pdo = $db->prepare('SELECT *,
CONCAT(s.firstname, ' ', s.name) AS teacher
FROM projects pj
LEFT JOIN school s ON pj.teacher=s.id 
WHERE project_id = :project_id ');  

$pdo->execute(array('project_id' => $project_id));
while ($row = $pdo->fetch(PDO::FETCH_ASSOC)) {
    echo $row["teacher"];
}

---

您可以使用concat..您可以使用concat..这将输出

firstnamename

作为教师列，您忘记包含空格。如果您查看原始问题，则没有空格，因此，我正在做同样的事情。

s.firstname.'''''.name as teacher

这将输出

firstname name

作为teacher列，您忘记包含空格。如果您查看原始问题，没有空格，因此我正在做同样的事情。

s.firstname.''.name as teacher