Dropping the last index if duplicated

Question

Why won't this code work as it should? When I double one of the entries, nickname or email, it will drop off the double new entry.

But if both nickname and email are same, it just won't delete the last entry, instead just insert a duplicate row.

Note: I have just an auto-incremented value for each row and no timestamp so I can not simply delete the latest entry, I have to make sure the last inserted entry is deleted.

EDIT: One could assume I could only use the upper if statement, but if I would do, BOTH entries would be deleted (if I took out the AND - part ofcourse)...

my code right now (PRIMARY KEY is KNR):

if(($doubleEmail || $doubleNickname) && !($doubleEmail && $doubleNickname))
        {
            mysql_query("DELETE FROM ".$sql['table']
            . " WHERE ".$sql['email']."='".mysql_real_escape_string($email)  
            . "' AND ".$sql['nick']."='".mysql_real_escape_string($nickName)."'");
            echo "double entry";
        }
elseif($doubleEmail && $doubleNickname) 
        {
            mysql_query("DELETE FROM ".$sql['table']." WHERE KNR > 
            ( ( SELECT MAX( KNR )-1 FROM ".$sql['table']."))");
            echo "double entry";

        }

Why don't you just make nickname & email a unique key so that the duplicate insert operation isn't allowed in the first place? — serakfalcon, Jan 19 '14 at 04:52

score 0 · Accepted Answer · edited May 23 '17 at 10:31

0

I'd suggest using

DELETE FROM `YOUR_TABLE` ORDER BY `YOUR_PRIMARY_KEY` DESC LIMIT 1

Your query generates a 1093 sql error. See this similar question: Deleting a row based on the max id

(On a side note: Always escape every and each value in your queries, even if they are not dynamic and come from config files.)

edited May 23 '17 at 10:31

Community

1
1

answered Jan 19 '14 at 04:29

Ke Vin

2,004
1
18
28

Dropping the last index if duplicated

1 Answers1