[英]How to get the result of the join operations?
每當我嘗試在drupal的功能模塊中執行此sql查詢時,我都無法獲得結果,但是當我嘗試在MySQL中執行此查詢時,我可以查看結果。 我的代碼如下所示:
function _get_subject_sub_category() {
$options = array();
$sql = "SELECT father.Subject_Code, child.Subject_Category
FROM {subjects} as child
INNER JOIN {subjects} as father ON (child.Parent_Category = father.Subject_Code
AND child.Level =2 )";
$result = db_query($sql);
foreach ($result as $row) {
$options[$row->father.Subject_Code] = $row->child.Subject_Category;
}
return $options;
}
我遇到的錯誤在$ options [$ row-> father.Subject_Code] = $ row-> child.Subject_Category;`行中。
任何幫助將不勝感激。
嘗試更改此行:
$options[$row->father.Subject_Code] = $row->child.Subject_Category;
對此:
$options[$row->Subject_Code] = $row->Subject_Category;
該表的名稱不在結果中。 如果需要避免混淆,可以在SQL查詢中使用別名。
我不了解drupal,也不使用php,但是我會說:
移走father.
在$row->father.Subject_Code
和
child.
在$row->child.Subject_Category
因為父親和孩子只是數據庫別名。
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