新WP_query（）和query_posts（）之间的区别

Question

A question about efficiency. What is the difference between using wp_query($args) and $query = new WP_Query($args)? Is there any difference in efficiency / the number of SQL queries? Is one always better than the other, or are there cases in which one style is preferred?

For example, if I want a complex page with 3 columns based on category, how are the following two examples different?

$query = new WP_Query("category_name=Issue 1")
while ($query->have_posts())....

vs.

rewind_posts()
query_posts("category_name=Issue 1")
while(have_posts())...

Answer 1

Nothing.

One just calls the other, this is from the WP source.

function query_posts($query) {
        $GLOBALS['wp_query'] = new WP_Query();
        return $GLOBALS['wp_query']->query($query);
}

God, I love WP, its soooo slick. Fail.