mysql - 如何在 SQL 中将 2 列合并为 1 列 TO 输出

Question

我有这个sql查询:

$sql = "SELECT d.doctor_name, a.patient_name, s.date, s.time FROM appointments AS a LEFT JOIN doctors AS d ON d.id = a.doctor_id LEFT JOIN slots AS s ON  s.id = a.slot_id WHERE s.date > '2019-10-01' ORDER BY d.doctor_name DESC ";

$result = $mysqli->query($sql);

echo '<pre>';
while ( $row = $result->fetch_assoc() ) {
    print_r($row);
}
echo '</pre>';

它的输出是:

Array
(
    [doctor_name] => Khaled
    [patient_name] => Nawaz
    [date] => 2019-10-11
    [time] => 02:01
)
Array
(
    [doctor_name] => Khaled
    [patient_name] => Anik
    [date] => 2019-10-07
    [time] => 02:31
)
Array
(
    [doctor_name] => Khaled
    [patient_name] => Manik
    [date] => 2019-10-02
    [time] => 03:31
)

我可以将date和time列合并为slot_date_time吗？

因此输出将是例如:

Array
(
    [doctor_name] => Khaled
    [patient_name] => Manik
    [slot_date_time] => 2019-10-02 03:31
)

Answer 1

尝试这个查询

SELECT d.doctor_name, a.patient_name, CONCAT(s.date, ',', s.time) AS slot_date_time  
FROM appointments AS a LEFT JOIN doctors AS d 
ON d.id = a.doctor_id LEFT JOIN slots AS s 
ON  s.id = a.slot_id 
WHERE s.date > '2019-10-01' 
ORDER BY d.doctor_name DESC

使用CONCAT将两列合并为一列