Question

I want to get post last modification/craetion dates by particular users and then echo it.

What I’m trying to do is:

<?php $id = get_the_ID();               

global $current_user;
$current_user = wp_get_current_user();

$postID = $id;  //assigning post id
$userID = $current_user->ID;  // assigning user ID

$sql = "SELECT post_date FROM wp_posts WHERE ID = $postID AND post_author = $userID ORDER BY post_date DESC LIMIT 1";
$userModifiedDate = $wpdb->query($sql);
echo $userModifiedDate; ?>

Where is my mistake? Can anyone lead me through this?

At the moment $userModifiedDate returns me 1.

Answer 1

$wpdb->query() returns the number of rows affected rather than the actual query result.

http://codex.wordpress.org/Class_Reference/wpdb#Run_Any_Query_on_the_Database

Try using a more specific function such as $wpdb->get_var() or $wpdb->get_results():

$userModifiedDate = $wpdb->get_var( $sql );

http://codex.wordpress.org/Class_Reference/wpdb#SELECT_a_Variable

Also, while it’s not absolutely necessary, I always like to pass any queries through $wpdb->prepare() first:

$sql = $wpdb->prepare( "SELECT post_date FROM wp_posts WHERE ID = %d AND post_author = %d ORDER BY post_date DESC LIMIT 1", $postID, $userID );

http://codex.wordpress.org/Class_Reference/wpdb#Protect_Queries_Against_SQL_Injection_Attacks