PHP - 如何从多个 sql 查询中分组

Question

我得到了

for($i = $start_date;$start_date <= $end_date;$i->modify('+1 day')) {
        $i->format('Y-m-d').'<br />';
    $dates = $i->format('Y-m-d');
    echo $query = "
SELECT md.dish_id
     , md.daydate
     , d.id
     , d.dish_name
     , d.weight
     , d.price 
  FROM dishes d
  LEFT 
  JOIN menu_details md 
    ON d.id = md.dish_id
 WHERE md.daydate = '$dates' 
";
     $result = mysql_query($query);
    }
     while($row = mysql_fetch_array($result)) {
        echo 'Date: '.$row['daydate'].'Name: '.$row['dish_name'].'<br />';
     }

如何在新的 row.In 数据库中为每个日期行 'dish_name' 有超过 1 行相同的日期=

Answer 1

您应该尽量避免运行循环查询...

尝试：

$query = "SELECT md.dish_id, md.daydate, d.id, d.dish_name, d.weight, d.price
FROM dishes d
LEFT JOIN menu_details md ON (d.id = md.dish_id)
WHERE md.daydate BETWEEN '$start_date' AND '$end_date'
GROUP BY md.daydate ";

$result = mysql_query($query);

while($row = mysql_fetch_array($result)) {
    echo 'Date: '.$row['daydate'].'Name: '.$row['dish_name'].'<br />';
}

分组依据是什么？我认为这可能会导致您丢失一些结果...

PHP - 如何从多个 sql 查询中分组

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