Question

I have a “profiles” table with

1. userid
2. key
3. key_value

obviously userid can have many rows
when a user logs in, I store userdata in a session_var
the query uses 3 tables:

1. users
2. profiles
3. openid

I had this,

$sql = "SELECT op.provider, g . * , gp . *, CONCAT(g.firstname, ' ', g.lastname) AS fullname
    FROM openid AS op
    INNER JOIN users AS g ON g.userid = op.userid
    INNER JOIN profiles AS gp ON gp.userid = op.userid
    WHERE op.openid =$openid";

but it returns multiple rows with duplicate data depending how many rows there are in the “profiles” table

This is not what I want. I need all the data in one row if that is possible

What is the most efficient solution? I also need it to store in a php array. How does php handle duplicate keys?

Answer 1

You probably want something like a distinct :

$sql = "SELECT distinct op.provider, g . * , gp . *, CONCAT(g.firstname, ' ', g.lastname) AS fullname
    FROM openid AS op
    INNER JOIN users AS g ON g.userid = op.userid
    INNER JOIN profiles AS gp ON gp.userid = op.userid
    WHERE op.openid =$openid";

That or you use a group by with the columns you want to have data grouped by.

Lastly, if you want to return multiple rows of data into a single field (but they are different) you could use a mysql group_concat() function to do so:

mysql> select * from first;
+------+-------+
| id   | title |
+------+-------+
|    1 | aaaa  |
|    2 | bbbb  |
|    3 | cccc  |
+------+-------+
3 rows in set (0.00 sec)

mysql> select group_concat(id) as IDs, group_concat(title) as Titles from first;
+-------+----------------+
| IDs   | Titles         |
+-------+----------------+
| 1,2,3 | aaaa,bbbb,cccc |
+-------+----------------+
1 row in set (0.00 sec)

Okay, I added some extra rows to my example table like this:

mysql> select * from first;
+------+-------+
| id   | title |
+------+-------+
|    1 | aaaa  |
|    2 | bbbb  |
|    3 | cccc  |
|    4 | NULL  |
|    5 | eeee  |
+------+-------+
5 rows in set (0.00 sec)

and now a group_concat returns this:

mysql> select group_concat(id) as IDs, group_concat(title) as Titles from first;
+-----------+---------------------+
| IDs       | Titles              |
+-----------+---------------------+
| 1,2,3,4,5 | aaaa,bbbb,cccc,eeee |
+-----------+---------------------+
1 row in set (0.00 sec)

But you can add a nice placeholder using the coalesce() function nicely like this:

mysql> select group_concat(id) as IDs, group_concat(coalesce(title,'NoValueSpecial')) as Titles from first;
+-----------+------------------------------------+
| IDs       | Titles                             |
+-----------+------------------------------------+
| 1,2,3,4,5 | aaaa,bbbb,cccc,NoValueSpecial,eeee |
+-----------+------------------------------------+
1 row in set (0.01 sec)

The coalesce() function looks at either multiple columns or a value you manually enter like I did and returns a great identifier to spot your missing field. It will evaluate left to right for the null values.