PHP查询未返回任何结果

Question

I'm probably missing something obvious but when I try to execute this query, it returns no results. I plugged it directly into MySQL and also tried replacing the variable with a valid row value and I get the correct output. When I use a variable, it gives me no results. Anyone have any thoughs?

    $query = "SELECT title FROM le7dm_pf_tasks WHERE project = (SELECT id FROM le7dm_pf_projects WHERE title = '".$ws_title."') ORDER BY title DESC LIMIT 1";

    $result_query = mysql_query($query) or die("Error: ".mysql_error());

    while ($row = mysql_fetch_assoc($result_query)) {
        $result_title = $row['title'];
    }

    $result_title = substr($result_title,0,6);
    echo $result_title;

Answer 1

Your SQL could do with some rework (though not the reason for your issue). No need for the nested select (which can also cause an error if it returns > 1 row). Try a join.

$sql = "
    SELECT title FROM le7dm_pf_tasks t
        INNER JOIN le7dm_pf_projects p ON t.project = p.id
    WHERE p.title = '{$ws_title}'
    ORDER BY title DESC LIMIT 1
";

You are also iterating over an unknown number of rows using the while statement. And then you exit and attempt a substring. How do you know that the last row iterated in the while had a value.

Try outputting $result_title inside the while loop itself to confirm data.

echo $result_title;

If you truly only have a single row, there is no need for the while loop. Just do

$row = mysql_fetch_assoc($result_query);

Answer 2

strip_tags($ws_title); - is what did it! The title was wrapped in an anchor tag that linked to that particular project page.

Thanks for all the good suggestions though. I'm gonna use some of them in the future when bug testing.