如何使用嵌套 SELECT 获取 INSERT 查询的插入行数？ 没有受影响的行，结果 ID，数量行

Question

The INSERT statement with SELECT in VALUES:

$stmt = $db->prepare("INSERT INTO weld_reference(weld_id,report_id) VALUES ((SELECT w.id FROM welds w WHERE w.weld_number=?),?)")

The below code loops through an array of user submited strings ($welds) and tries insert its ID into table weld_reference if it exists in table welds .

    $stmt->bind_param("si",$weld_number,$_POST['report_id']);
    foreach($welds as $weld_number){
        if($stmt->execute() and $stmt->num_rows){
            ++$insert_count;
        }
    }   

I don't want to do another query to see if the row exists, I was hoping that I could get the number of rows or success of the INSERT after each $stmt->execute().

However, $stmt->affected_rows , and $stmt->insert_id always returns 1 and $stmt->num_rows always returns 0 whether a row was inserted or not.

How can I get a read on this and see if a row has been inserted to send an accurate feedback message to the user?

Answer 1

How do you check the value of $stmt->insert_id ? Because it should return you "Get the ID generated from the previous INSERT operation". If ou only ($evaluate) it it will return true (as 1)

The way i do it is i store the id's in an array so i can have a nice list of what has been inserted.

$stmt->bind_param("si",$weld_number,$_POST['report_id']);
    foreach($welds as $weld_number){
        if($stmt->execute()){
          $insertedId[]=$stmt->insert_id;
        }
    } 
echo count($insertedId);

Or since an id would logicaly never be empty you could do

$stmt->bind_param("si",$weld_number,$_POST['report_id']);
    foreach($welds as $weld_number){
        if($stmt->execute() && !empty($stmt->insert_id)){
            $insert_count++;
           // ++$insert_count; //unaware of this syntax -.-
        }
    }