why the current date do not update

Question

I'm using the following query to update fields in my table if token is matching, but the current date is not getting inserted

$this->wpdb->update(  
            'wp_competitors',  
            array(  
                'results' => $tips,  // json  
                'update_time' => ' CURDATE()' //  
            ),  
            array( 'token' => $token ),  
            array(  
                '%s',   // value1  
                '%d'    // value2  
            ),  
            array( '%d' )  
        );  

than I was trying to use php's date('Y-m-d H:i:s') but no results

Answer 1

From the codex:

<?php $wpdb->update( $table, $data, $where, $format = null, $where_format = null ); ?>

In your exampe ' CURDATE()' is simply a string, not a MySQL function (or something else).

The correct syntax for php's date() is:

date( [format], [timestamp] )

Try this:

$this->wpdb->update(  
            'wp_competitors',  
            array(  
                'results' => $tips,  // json  
                'update_time' => date( 'Y-m-d H:i:s', time() )
            ),  
            array( 'token' => $token ),  
            array(  
                '%s',   // value1  
                '%d'    // value2  
            ),  
            array( '%d' )  
        );

Better than php's date() is WordPress current_time():

current_time( 'mysql' )

This will return something similiar to 2012-12-02 23:00:08