如何在 sql 中检索当年有记录的月份名称列表？

Question

How do you retrieve a list of Months where there are records for a specific client by a specific year?

My table table name is called Date that has entries as DATE: 2019-11-21.

I've tried grouping by Month by I think I need to use something with AS to get the month name?

$sql = "SELECT * FROM Requests WHERE Client_id = ? GROUP BY MONTH";
$stmt = $db->prepare($sql);
$stmt->bind_param("i", $id);
$stmt->execute();   
$data = $stmt->get_result();
$stmt->close();

if(mysqli_num_rows($data) === 0){
    echo "<br>no results";
}else{
    echo "<br>Results<br>";
}

while($row=mysqli_fetch_array($data)){
?>
     /* Desired Output:
         Each Month Name
     */
<?php
}

Answer 1

month is a function in mysql. So unless you have a column named month (not a good idea), then you need to use it properly. If your date column is named date , then you would pass that to the month function.

$sql = "SELECT MONTH(`date`), * 
        FROM Requests 
        WHERE Client_id = ? 
        GROUP BY MONTH(`date`)";

If you want to restrict it to a specific year, add that to the where request:

$sql = "SELECT MONTH(`date`), * 
        FROM Requests 
        WHERE Client_id = ? 
        AND YEAR(`date`) = '2019' 
        GROUP BY MONTH(`date`)";

(as placeholder)

$sql = "SELECT MONTH(`date`), * 
        FROM Requests 
        WHERE Client_id = ? 
        AND YEAR(`date`) = ? 
        GROUP BY MONTH(`date`)";
$stmt = $db->prepare($sql);
$stmt->bind_param("ii", $id, $year);

Note that this will actually group the results together (one row per month), not order them, so you may not be getting what you want.