从一个表插入数据到另一个PHP SQL

Question

I'm making a private messages application and I am trying to create a 'deleted messages' folder so the messages that the user wants to delete from their inbox or sent folder go to 'deleted'. I managed to write the code to delete them completely however that is not what i want. I created another table in my database, named 'deleted' so I'm trying to delete them from the inbox and then insert them there.

This is what I have until now:

if ( isset($_GET['delete'])) {
    $multiple = $_GET['multiple'];

$i=0;
$q = "insert into deleted  (select * from email where to_user = '$user')";
foreach($multiple as $msg_id) 
{ 
        $i++;

    if ($i==1) {
        $q .= " WHERE id = ". mysql_real_escape_string($msg_id)."";
    } else {
        $q .= "OR  id = ". mysql_real_escape_string($msg_id)."";
    }
}

mysql_query($q) or die (mysql_error());
header("location: " .$_SERVER['PHP_SELF']);
exit();
}

It is giving me this error:

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHERE id = 14' at line 1

Answer 1

The output of this script would be:

insert into deleted  (select * from email where to_user = '$user') WHERE id = 14

You can't have a WHERE on the insert clause. What you are probably looking for is:

insert into deleted  (select * from email where to_user = '$user' AND id = 14)

Which you can account for by adjusting the position of the closing bracket, and adjusting the WHERE clause to be listed as AND instead.

On further reflection, this ALSO will not accomplish what you want. You are attempting to join Multiple ID's together, but the way AND and OR in SQL work, this will not accomplish what you are attempting. The OR statement would need to be wrapped in brackets to ensure it got caught with the AND statement, like so:

INSERT INTO deleted  (SELECT * FROM email WHERE to_user = '$user' AND (id = 14 OR id = 15))

Your code should read like this:

$q = "insert into deleted  (select * from email where to_user = '$user' ";
foreach($multiple as $msg_id) 
{ 
    $i++;

    if ($i==1) {
        $q .= " AND (id = ". mysql_real_escape_string($msg_id)."";
    } else {
        $q .= " OR  id = ". mysql_real_escape_string($msg_id)."";
    }
}
$q .= "))"; // Closing out both brackets

Answer 2

why are deleting from this school syntax. Use Triggers

something like this :

CREATE TRIGGER `my_insert_table2_trigger`     
  AFTER DELETE ON `table1`     
  FOR EACH ROW     
BEGIN
  INSERT INTO `table2` VALUES (OLD.id, OLD.Column_with_value)
END

Answer 3

Just a thought - you could also add a column to your table - 'DELETED_FLAG' perhaps? - that you can set to "Y" when you want it to appear as 'deleted.'

It'll save some complexity in the long run.

Answer 4

Problem is you have two WHERE clause mentioned in your query as pointed below. Also, remove those () from select part

$q = "insert into deleted  
(select * from email where to_user = '$user')"; <-- Here

foreach($multiple as $msg_id) 
{ 
     if ($i==1) {
        $q .= " WHERE id = ". mysql_real_escape_string($msg_id).""; <-- Here