php 数组到字符串转换错误
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Array to string conversion error
提问by Dylan Buth
I have a query that's pulling a list of IDs. Those IDs are in an array and I need to search another table with those IDs. I tried using implode to make those IDs a string that I could use in a where clause but I keep getting this error.
我有一个查询正在提取 ID 列表。这些 ID 在一个数组中，我需要用这些 ID 搜索另一个表。我尝试使用 implode 使这些 ID 成为我可以在 where 子句中使用的字符串，但我不断收到此错误。
My current code is:
我目前的代码是：
$query = $this->db->query('
SELECT *
FROM system_scoperights
WHERE user = '. $this->session->userdata('username') .'
');
foreach ($query->result() as $row) {
$scope = $row->site;
$data[] = $scope;
}
$dataScope[] = $data;
$idList = implode(',', $dataScope); <---- Error Line
$where = 'WHERE scope_scopes.sc_ID IN '. $idList .'';
I've tried different things I found on forums like:
我尝试了在论坛上发现的不同内容，例如：
$idList = implode(',', array_values($dataScope));
and
和
$idList = implode(',', join($dataScope));
but none of those work. (I've never even heard of the join function)
但这些都不起作用。（我什至从未听说过 join 功能）
Thanks in advance for the help.
在此先感谢您的帮助。
回答by Jay
$dataScope[] = $data;
but
但
$data[] = $scope;
therefore $dataScopehas an array inside it's array. implodeonly work on one level, so that why you're getting this error.
因此$dataScope它的数组中有一个数组。implode仅在一个级别上工作，因此您会收到此错误。
You should note that this is actually possible in SQL:
您应该注意到这在 SQL 中实际上是可能的：
SELECT * FROM some_table WHERE id IN (SELECT site FROM another_table WHERE ... )
which would eliminate the entire need for this code.
这将消除对这段代码的全部需求。
That is:
那是：
$where = 'WHERE scope_scopes.sc_ID IN (SELECT site
FROM system_scoperights
WHERE user = '. $this->session->userdata('username') . ')';
回答by lerxstrulz
I partially agree with Jay's answer...just remove the line:
我部分同意 Jay 的回答......只需删除该行：
$dataScope[] = $data
and use the $datavariable directly since it's already an array:
并$data直接使用该变量，因为它已经是一个数组：
$idList = implode(',', $data);
However you also should use ( and ) in your where clause:
但是，您也应该在 where 子句中使用 (和)：
$where = 'WHERE scope_scopes.sc_ID IN (' . $idList . ')';
Using sub-queries in your where clauses, although they do have their place at times, can cost a lot of overhead, especially using 'SELECT *'. Never ask for more than you need from your db tables :)
在您的 where 子句中使用子查询，虽然它们有时确实有其一席之地，但会花费大量开销，尤其是使用“SELECT *”。永远不要从你的数据库表中要求超过你需要的 :)
