我在数据库中有信息需要以奇怪的方式排序。我在下面有一个非常简化的版本。
我需要按照NEXTPAGEID列所指示的顺序使用PHP输出它们。有人告诉我只是循环遍历值,但我无法找出正确的方法来循环它们。
ID: 1; NEXTPAGEID: 3
ID: 3; NEXTPAGEID: 118
ID: 9; NEXTPAGEID: 10
ID: 10; NEXTPAGEID: 515
ID: 11; NEXTPAGEID: 12
ID: 118; NEXTPAGEID: 9
所以我真正需要的顺序是
ID: 1, 3, 118, 9, 10, 515, (whatever the NEXTPAGEID of 515 is)
等。
答案 0 :(得分:2)
这需要支持MySQL
缺少的递归查询。
你可以这样模仿它:
SELECT @r := 1, @c := 0 -- the first id
SELECT t.*
FROM (
SELECT @r AS _current_id,
@r :=
(
SELECT nextpageid
FROM mytable
WHERE id = _current_id
) AS _next_id,
@c := @c + 1 AS _orderer
FROM mytable t
) q
JOIN mytable t
ON t.id = q._current_id
ORDER BY
_orderer
答案 1 :(得分:1)
SELECT * FROM `table_name` ORDER BY `NEXTPAGEID` ASC
答案 2 :(得分:0)
如果您不想进行递归SQL查询,可以使用PHP进行排序:
function sort_by_nextpageid($array) {
$index = array();
foreach($array as $row) $index[$row['ID']] = $row;
$result = array();
$id = 1;
while (isset($index[$id])) {
$result[] = $index[$id];
$id = $index[$id]['NEXTPAGEID'];
}
return $result;
}
并调用这样的函数:
// rows from the db
$array = array(
array('ID' => 1, 'NEXTPAGEID' => 3),
array('ID' => 3, 'NEXTPAGEID' => 118),
array('ID' => 9, 'NEXTPAGEID' => 10),
array('ID' => 10, 'NEXTPAGEID' => 515),
array('ID' => 11, 'NEXTPAGEID' => 12),
array('ID' => 118, 'NEXTPAGEID' => 9),
);
$array = sort_by_nextpageid($array);
答案 3 :(得分:-1)
$query = "SELECT * FROM `table_name`";
$result = mysql_result($query);
if(mysql_num_rows($result)>0){
while($rows=mysql_fetch_assoc($result)){
$testArray[] = $rows[ID];
$testArray[] = $rows[NEXTPAGEID];
}
$result2 = array_unique($result);
$lastArray=array_values($result2);