Question

I have a table with 3 cols, incremeting id, name, and data

What i’m trying to achieve

you enter a $name… and returns $data…
then
it takes $data and finds all $names that have the same $data.

SELECT * FROM table WHERE name ='$name' data='$data' and data!='0'

does not seem to cut it..

I’m basically trying to get all rows that have the same data as the entered $name’s $data.

thanks in advance.

Answer 1

You may want to try the following:

SELECT  t2.name
FROM    `table` t1
JOIN    `table` t2 ON (t2.data = t1.data)
WHERE   t1.name = '$name' AND t1.data != '0';

Test case:

CREATE TABLE `table` (id int, name varchar(10), data varchar(10));

INSERT INTO `table` VALUES (1, 'name1', 'data-a');
INSERT INTO `table` VALUES (2, 'name2', 'data-b');
INSERT INTO `table` VALUES (3, 'name3', 'data-a');
INSERT INTO `table` VALUES (4, 'name4', 'data-b');
INSERT INTO `table` VALUES (5, 'name5', 'data-a');

Result:

SELECT  t2.name
FROM    `table` t1
JOIN    `table` t2 ON (t2.data = t1.data)
WHERE   t1.name = 'name2' AND t1.data != '0';

+-------+
| name  |
+-------+
| name2 |
| name4 |
+-------+
2 rows in set (0.00 sec)

The nested query solution suggested by @Borealid is another valid solution that returns the same result:

SELECT  name 
FROM    `table` 
WHERE   data IN (SELECT data FROM `table` WHERE name = 'name2');

+-------+
| name  |
+-------+
| name2 |
| name4 |
+-------+
2 rows in set (0.00 sec)