将表的结果插入到具有两个foreach循环的另一个表中

Question

I am trying to get the result of a table and insert it into another table. The results are user id's. This code should work, but it doesn't.

$query1 = "SELECT id FROM users";                           
$select1 = $db->prepare($query1);
$select1->execute(array());  
foreach($select as $index => $rs) {

    $users = $rs['id'];

    // the results are 1,2,3,4,5,6,7,8... (the user id's)

}



// Here below, I want to add the results into another table...

foreach ($users as $row){
    $query2 = "INSERT INTO validateuser (userid) VALUES (".$row.")";

    $select2 = $db->prepare($query2);
    $select2->execute(array());  
}

Answer 1

This seems over-complicated to me. Why not let the database do what databases do best - handle data, and perform this in a single insert-select statement?

INSERT INTO validateuser (userid)
SELECT id FROM users

EDIT:
To answer the concern raised in the comments, the 'validated' value could be selected as a literal:

INSERT INTO validateuser (userid, validated)
SELECT id, 'validated' FROM users

Answer 2

As you iterate the results of the first query with foreach($select as $index => $rs) , you set $users to the id of each row of the results with $users = $rs['id']; .

At the end of your loop, $users will contain the id of the last row because it's being overwritten each time. It's not iterable (it's an int), so foreach ($users as $row){ doesn't make sense.

You probably meant to do $users[] = $rs['id']; instead. But if you're just inserting them all, you might as well just do it in one query like the other answer suggests.