Question

I want to use multiple table to get recent post (Q) and user name (handle) but when I am trying to get with this code it is giving error

Table Name qa_posts and qa_users and need to connect userid from qa_posts to handle from qa_users

SELECT *
FROM qa_posts, qa_users
WHERE type="Q" AND qa_posts.userid = "qa_users.handle"
ORDER BY created DESC
LIMIT 5

Error message

SELECT *
FROM qa_posts, qa_users
WHERE qa_posts.userid = "qa_users.handle"
ORDER BY created DESC
LIMIT 5

Error 1052: Column 'created' in order clause is ambiguous

Actual Code

qa_db_connection();
$query_post = qa_db_query_raw('         
    SELECT *
    FROM qa_posts, qa_users
    WHERE type="Q" AND qa_posts.userid = "qa_users.handle"
    ORDER BY created DESC
    LIMIT 5

') or die(mysql_error());

while($row = mysql_fetch_array($query_post)) {
    echo $row['title'];
    echo '<span style="font-size:65%;font-style:italic">'.$row['created'].'</span>';
    echo '<br/>';
}

See this image for table structure

Answer 1

The given error cames out when you do have same name column in both table…So you have to specify column name along with table name like in following patter:

table_name.column_name

So, your query should be like this:

SELECT *
FROM qa_posts, qa_users
WHERE qa_posts.userid = "qa_users.handle"
ORDER BY qa_posts.created DESC (or put the ORDER BY qa_users.created DESC if you want to make order by `created` of `qa_users` )
LIMIT 5

If you really not desired to have userid of value “qa_users.handle”, you should not quote them and should have query like this:

    SELECT *
    FROM qa_posts, qa_users
    WHERE qa_posts.userid = qa_users.userid AND qa_posts.type="Q" 
    ORDER BY qa_posts.created DESC 
    LIMIT 5

You would better to use JOIN in following way:

    SELECT *
    FROM qa_posts INNER JOIN qa_users ON qa_posts.userid = qa_users.userid 
    WHERE qa_posts.type="Q" 
    ORDER BY qa_posts.created DESC 
    LIMIT 5