num_rows不返回任何值

Question

I'm using the following code to find the number of rows returned:

global $wpdb;

$results = $wpdb->get_results("SELECT * FROM list WHERE queue = 1 ORDER BY id ASC LIMIT 0,1");

$rowcount = $results->num_rows;
echo $rowcount;

As you can see, the results are limited to 1 row, and when I run this query in SQL it returns 1 row just fine. But in PHP the $rowcount doesn't return any value at all.

Any ideas what might be wrong? I get no error.

Answer 1

I think you need to use count($results) since the method $wpdb->get_results returns a array of objects/arrays.

Another way to get the number of rows is to use $wpdb->num_rows . Apparently this works for $wpdb->get_results .

From the docs ( http://codex.wordpress.org/Class_Reference/wpdb ), it says the following about get_results:

Generic, multiple row results can be pulled from the database with get_results. The function returns the entire query result as an array. Each element of this array corresponds to one row of the query result and, like get_row, can be an object, an associative array, or a numbered array. If no matching rows are found, or if there is a database error, the return value will be an empty array. If your $query string is empty, or you pass an invalid $output_type, NULL will be returned.