Ex : i have 2 sql tables, table1 & table2.
table1 have 3 rows = id1, id2, id3
table2 have 4 rows = id1, id2, id3, id4
Now i want to print/delete only id4 from table2. I tried several methods, but i cant. please help me.
so table2 looks like this?
id, someothercolumn, evenanothercolumn
1, x, y
2, x, y
3, x, y
4, x, y
Just do
SELECT * FROM table2 WHERE id = 4
or
DELETE FROM table2 WHERE id = 4
[hr]
If it doesn’t look like this then please add the database schema. Easy way to get it is to open phpmyadmin, select export, select table2 and copy/paste the stuff you get from doing that.
Dear JimL, Thank you for reply.
Your answer is correct, but how to find “id4” is not in table1 ?
[it is problem for me because hundreds of ids/rows in both tables, so i want find only which is not in both tables. like id4 ]
We’re going off of what you used for examples, jim gave you a basic example of how to pull just one thing from your tables, but since you have 2 tables, a simple example would be:
mysql_query(“SELECT * FROM table1, table2 WHERE x <> y”);
That’s assuming that column x is available in both tables. <> is the sql equivalent to !=.
Ah, I see.
This should be what you’re looking for
SELECT table2.id
FROM table2
WHERE table2.id NOT IN (SELECT table1.id FROM table1)
hi I am using this code for query : [php]
$SQL = mysql_query("SELECT * FROM table1,table2
WHERE table1.id != table2.id
");
while ($row = mysql_fetch_assoc($SQL)) {
echo $id = $row[‘id’];
echo ‘
’ ;
}
[/php]
but result is blank, is my code correct or not ?
Hi JimL,
Your answer is correct, my problem is solved, thanks a lot. 