php - 查询中的递归求和

Question

我有一个表，其中的数据使用邻接表分层存储，如下例所示

id     account parent
1      root    null
2      a1      1
3      b1      1
4      a2      2
5      a3      4
6      a4      2
7      b2      3

And a table where I keep values for these accounts

id_account    value
2             10
2             10
4             20
5             30
6             10 

I made a function which returns all child account given a parent account:

function getChildrenAccount($parent_id)
  {
    $query = "SELECT id, account FROM accounts WHERE parent='{$parent_id}' ORDER BY account";
    $result = mysql_query($query) or die(mysql_error());
    while($r[]=mysql_fetch_assoc($result));
    return $r;
  }

我想做的是一个函数，它不仅返回子帐户，还返回所有值的总和，包括每个结果的子帐户。例如

getChildrenAccount(4)

将返回具有以下语法的数组

array(1) { 
  [0]=> array(3) { 
     ["id"]=> 5
     ["account"]=> "a3"
     ["sum"]=> 50 //a2 + a3
}

And

getChildrenAccount(2)

array(2) { 
  [0]=> array(3) { 
     ["id"]=> 4
     ["account"]=> "a2"
     ["sum"]=> 70 //a1 + a2 + a3
  [1]=> array(3) { 
     ["id"]=> 6
     ["account"]=> "a4"
     ["sum"]=> 30 //a1 + a4
}

我想我必须在我的 while 语句中使用某种递归，但我有点困惑。你能帮帮我吗？

谢谢

Answer 1

function getChildrenAccount($accountID){

   $query = ' SELECT id,account,sum(value) as `SUM`
    FROM accounts,accountsValues
    WHERE accounts.id = accountsValues.id_accounts
    AND id = $accountID 
    OR id IN (SELECT id FROM accounts where parent = $accountID) ';
....
}