我希望有人可以帮我解决这个问题。
假设我有3个数据库表：
Users:
user_id, user_name
100, John
101, Jessica
Cars:
car_id, car_name
30, Corvette
31, BMW
UsersCars:
user_id, car_id, car_colour
100, 30, Red
101, 30, Green
101, 31, Green
(so John got a red corvette and Jessica has a green Corvette and a BMW)
我想让代码返回多维PHP数组，如：
Array
(
[100] => Array
(
[user_id] => 100
[user_name] => John
[cars] => Array
(
[car_id]=>30,
[car_name]=>'Corvette',
[car_colour]=>'Red'
)
)
[101] => Array
(
[user_id] => 101
[user_name] => Jessica
[cars] => Array
(
[0] => Array
(
[car_id]=>30,
[car_name]=>'Corvette',
[car_colour]=>'Green'
),
[1] => Array
(
[car_id]=>31,
[car_name]=>'BMW',
[car_colour]=>'Green'
)
)
)
)
我有以下SQL
SELECT u.*, c.* FROM Users u
LEFT JOIN UsersCars uc ON u.user_id = uc.user_id
LEFT JOIN Cars c ON uc.car_id = c.car_id
和PHP
$result = mysqli_query($db, $q);
while ($row = mysqli_fetch_assoc($result)) {
$users_with_cars[$row['user_id']] = $row;
}
但这不正确。任何人都知道如何解决这个导致上面的数组（考虑到性能）？我宁愿不想硬编码“汽车”的例外情况，这种情况可能不止一次发生。我宁愿看一些只看$ row和$ users_with_cars的内容，当看到一些新值时，它会通过将旧值转换为数组来附加它。也许已经有一个原生的PHP功能呢？或者更好，也许我的MySQL或整个方法是错误的？
任何帮助或提示表示赞赏。
此致
更新已解决
这是一个更新，也许我可以帮助别人我最终如何解决它。
我最终总是使用一个或多个汽车的数组，我调整了表格以始终以“id”作为列名。这样您就可以轻松扩展它。见例子;
Users:
id, name
100, John
101, Jessica
Cars:
id, name
30, Corvette
31, BMW
UsersCars:
user_id, car_id, car_colour
100, 30, Red
101, 30, Green
101, 31, Green
$q = 'SELECT u.*, c.id as car_id, c.name as car_name, uc.colour as car_colour FROM Users u
LEFT JOIN UsersCars uc ON u.id = uc.user_id
LEFT JOIN Cars c ON uc.car_id = c.id';
$result = mysqli_query($db, $q);
while ($row = mysqli_fetch_assoc($result)) {
$users_with_cars[] = $row;
}
$joins = array('cars' => array('car_id'=>'id','car_name'=>'name','car_colour'=>'colour'));
$users_with_cars = create_join_array($users_with_cars, $joins);
print_r($users_with_cars);
function create_join_array($rows, $joins){
/* build associative multidimensional array with joined tables from query rows */
foreach((array)$rows as $row){
if (!isset($out[$row['id']])) {
$out[$row['id']] = $row;
}
foreach($joins as $name => $item){
unset($newitem);
foreach($item as $field => $newfield){
unset($out[$row['id']][$field]);
if (!empty($row[$field]))
$newitem[$newfield] = $row[$field];
}
if (!empty($newitem))
$out[$row['id']][$name][$newitem[key($newitem)]] = $newitem;
}
}
return $out;
}
这一切都产生了漂亮的阵列：
Array
(
[100] => Array
(
[id] => 100
[name] => John
[cars] => Array
(
[30] => Array
(
[id]=>30
[name]=>'Corvette',
[colour]=>'Red'
)
)
)
[101] => Array
(
[id] => 101
[name] => Jessica
[cars] => Array
(
[30] => Array
(
[id]=>30,
[name]=>'Corvette',
[colour]=>'Green'
),
[31] => Array
(
[id]=>31,
[name]=>'BMW',
[colour]=>'Green'
)
)
)
)
假设用户也可以拥有多辆自行车。然后，您有多个连接数组，您可以轻松地使用左连接绑定并将其添加到连接数组。
$q = 'SELECT u.*, c.id as car_id, c.name as car_name, uc.colour as car_colour, b.id as bike_id, b.name as bike_name FROM Users u
LEFT JOIN UsersCars uc ON u.user_id = uc.user_id
LEFT JOIN Cars c ON uc.car_id = c.id
LEFT JOIN UsersBikes ub ON u.user_id = ub.user_id
LEFT JOIN Bikes b ON ub.bike_id = b.id';
$result = mysqli_query($db, $q);
while ($row = mysqli_fetch_assoc($result)) {
$users_with_cars_bikes[] = $row;
}
$joins = array('cars' => array('car_id'=>'id', 'car_name'=>'name', 'car_colour'=>'colour'),
'bikes' => array('bike_id'=>'id', 'bike_name'=>'name'));
$users_with_cars_bikes = create_join_array($users_with_cars_bikes, $joins);
print_r($users_with_cars_bikes);
会导致类似
的内容Array(
[100] => Array
(
[id] => 100
[name] => John
[cars] => Array
(
[30] => Array
(
[id]=>30
[name]=>'Corvette',
[colour]=>'Red'
)
)
[bikes] => Array
(
[41] => Array
(
[id]=>41
[name]=>'BMX'
)
)
)
)
依旧......
感谢大家帮忙：）
答案 0 :(得分：1)
这是我能想到的。它（可能）会像您想要的输出一样创建一个数组。不知道它是否会起作用，我在这里写了这个没有测试。让我知道！ ：）
$result = mysqli_query($db, $q);
while ($row = mysqli_fetch_assoc($result))
{
// Add user ID and name to the array
$users_with_cars[$row['user_id']]['user_id'] = $row['user_id'];
$users_with_cars[$row['user_id']]['user_name'] = $row['user_name'];
// Check if this user has cars in the array. If not, this is the first car (see else)
if(isset($users_with_cars[$row['user_id']]['cars']))
{
// Check if there is exactly 1 car in the array
if(count($users_with_cars[$row['user_id']]['cars']) == 1)
{
// If yes, put that car in a 'sub array'
$users_with_cars[$row['user_id']]['cars'] = array(0 => $users_with_cars[$row['user_id']]['cars']);
// Then add the new car
$users_with_cars[$row['user_id']]['cars'][] = array('car_id' => $row['car_id'], 'car_name' => $row['car_name'], 'car_color' => $row['car_color']);
}
else
{
// It already has more than one car in the array. Just add it
$users_with_cars[$row['user_id']]['cars'][] = array('car_id' => $row['car_id'], 'car_name' => $row['car_name'], 'car_color' => $row['car_color']);
}
}
else
{
// Add a single car without 'sub array'
$users_with_cars[$row['user_id']]['cars']['car_id'] = $row['car_id'];
$users_with_cars[$row['user_id']]['cars']['car_name'] = $row['car_name'];
$users_with_cars[$row['user_id']]['cars']['car_color'] = $row['car_color'];
}
}
<小时/> 修改
这是我在评论中提到的一个例子：
$result = mysqli_query($db, $q);
while ($row = mysqli_fetch_assoc($result))
{
$count = count($users_with_cars[$row['user_id']]['cars']);
foreach($row AS $key => $value)
{
if(substr($key, 0, 4) == "car_")
{
// Single:
$users_with_cars[$row['user_id']]['cars'][$key] = $value;
// Multiple:
$users_with_cars[$row['user_id']]['cars'][$count][$key] = $value;
}
}
}
答案 1 :(得分：0)
$result = mysqli_query($db, $q);
$users_with_cars = array();
while ($row = mysqli_fetch_assoc($result)) {
if (!isset($users_with_cars[$row['user_id']])) {
$user = array();
$user['user_id'] = $row['user_id'];
$user['user_name'] = $row['user_name'];
$user['cars'] = array();
$users_with_cars[$row['user_id']] = $user;
}
$car = array();
$car['car_id'] = $row['car_id'];
$car['car_name'] = $row['car_name'];
$car['car_colour'] = $row['car_colour'];
$users_with_cars[$row['user_id']]['cars'] = $car;
}