Wordpress menggabungkan kueri

Ini adalah versi jawaban yang diperbarui, yang lebih fleksibel daripada yang sebelumnya.

Inilah satu ide menggunakan SQL UNION :

• Kita dapat menggunakan data dari posts_clauses filter untuk menulis ulang kueri SQL dari posts_request Saring.

• Kami memperluas WP_Query kelas untuk mencapai tujuan kami. Kami benar-benar melakukannya dua kali:

  • WP_Query_Empty :untuk mendapatkan kueri SQL yang dihasilkan dari setiap subkueri, tetapi tanpa melakukan kueri basis data.
  • WP_Query_Combine :untuk mengambil postingan.

• Implementasi berikut mendukung penggabungan N sub-kueri.

Berikut adalah dua demo:

Demo #1:

Mari kita asumsikan Anda memiliki enam posting, diurutkan berdasarkan tanggal (DESC):

CCC
AAA
BBB
CCC
YYY
ZZZ
XXX 

di mana XXX , YYY dan ZZZ lebih tua dari DT=2013-12-14 13:03:40 .

Yuk order postingan kita agar postingan dipublish setelah DT diurutkan berdasarkan judul (ASC) dan posting dipublikasikan sebelum DT diurutkan berdasarkan judul (DESC):

AAA
BBB
CCC
ZZZ
YYY
XXX 

Kemudian kita dapat menggunakan yang berikut ini:

/**
 * Demo #1 - Combine two sub queries:
 */

$args1 = array(
    'post_type'  => 'post',
    'orderby'    => 'title',
    'order'      => 'ASC',
    'date_query' => array(
        array( 'after' => '2013-12-14 13:03:40' ),
    ),
);

$args2 = array(
    'post_type'  => 'post',
    'orderby'    => 'title',
    'order'      => 'DESC',
    'date_query' => array(
        array( 'before' => '2013-12-14 13:03:40', 'inclusive' => TRUE ),    
    ),
);

$args = array( 
   'posts_per_page' => 1,
   'paged'          => 1,
   'sublimit'       => 1000,
   'args'           => array( $args1, $args2 ),
);

$results = new WP_Combine_Queries( $args );

Ini menghasilkan kueri SQL berikut:

SELECT SQL_CALC_FOUND_ROWS * FROM ( 
    ( SELECT wp_posts.* 
        FROM wp_posts 
        WHERE 1=1 
            AND ( ( post_date > '2013-12-14 13:03:40' ) ) 
            AND wp_posts.post_type = 'post' 
            AND (wp_posts.post_status = 'publish' OR wp_posts.post_status = 'private') 
            ORDER BY wp_posts.post_title ASC 
            LIMIT 1000
    ) 
    UNION 
    ( SELECT wp_posts.* 
        FROM wp_posts 
        WHERE 1=1 
        AND ( ( post_date <= '2013-12-14 13:03:40' ) ) 
        AND wp_posts.post_type = 'post' 
        AND (wp_posts.post_status = 'publish' OR wp_posts.post_status = 'private') 
        ORDER BY wp_posts.post_title DESC 
        LIMIT 1000
    ) 
) as combined LIMIT 0, 10 

Demo #2:

Ini contoh Anda:

/**
 * Demo #2 - Combine two sub queries:
 */

$today = date( 'm/d/Y', strtotime( 'today' ) );

$args1 = array(
    'post_type'      => 'workshops',
    'meta_key'       => 'select_dates_0_workshop_date',
    'orderby'        => 'meta_value',
    'order'          => 'ASC',
    'meta_query'     => array(
        array(
            'key'         => 'select_dates_0_workshop_date',
            'value'       => $today,
            'compare'     => '>=',
            'type'        => 'CHAR',
        ),
    )
);

$args2 = array(
    'post_type'      => 'workshops',
    'meta_key'       => 'select_dates_0_workshop_date',
    'orderby'        => 'meta_value',
    'order'          => 'DESC',
    'meta_query'     => array(
        array(
            'key'         => 'select_dates_0_workshop_date',
            'value'       => $today,
            'compare'     => '<',
            'type'        => 'CHAR',
        ),
    )
);

$args = array( 
   'posts_per_page' => 5,
   'paged'          => 4,
   'sublimit'       => 1000,
   'args'           => array( $args1, $args2 ),
);

$results = new WP_Combine_Queries( $args );

Ini akan memberi Anda kueri seperti ini:

SELECT SQL_CALC_FOUND_ROWS * FROM ( 
    ( SELECT wp_posts.* 
        FROM wp_posts 
        INNER JOIN wp_postmeta ON (wp_posts.ID = wp_postmeta.post_id) 
        INNER JOIN wp_postmeta AS mt1 ON (wp_posts.ID = mt1.post_id) 
        WHERE 1=1 
            AND wp_posts.post_type = 'workshops' 
            AND (wp_posts.post_status = 'publish' OR wp_posts.post_author = 1 AND wp_posts.post_status = 'private') 
            AND (wp_postmeta.meta_key = 'select_dates_0_workshop_date' AND (mt1.meta_key = 'select_dates_0_workshop_date' AND CAST(mt1.meta_value AS CHAR) >= '05/16/2014') ) 
            GROUP BY wp_posts.ID 
            ORDER BY wp_postmeta.meta_value ASC
            LIMIT 1000 
        ) 
    UNION 
    ( SELECT wp_posts.* 
        FROM wp_posts 
        INNER JOIN wp_postmeta ON (wp_posts.ID = wp_postmeta.post_id) 
        INNER JOIN wp_postmeta AS mt1 ON (wp_posts.ID = mt1.post_id) 
        WHERE 1=1 
            AND wp_posts.post_type = 'workshops' 
            AND (wp_posts.post_status = 'publish' OR wp_posts.post_author = 1 AND wp_posts.post_status = 'private') 
            AND (wp_postmeta.meta_key = 'select_dates_0_workshop_date' AND (mt1.meta_key = 'select_dates_0_workshop_date' AND CAST(mt1.meta_value AS CHAR) < '05/16/2014') ) 
            GROUP BY wp_posts.ID 
            ORDER BY wp_postmeta.meta_value DESC 
            LIMIT 1000 
        ) 
) as combined LIMIT 15, 5

Demo #3:

Kami juga dapat menggabungkan lebih dari dua sub kueri:

/**
 * Demo #3 - Combine four sub queries:
 */

$args = array( 
   'posts_per_page' => 10,
   'paged'          => 1,
   'sublimit'       => 1000,
   'args'           => array( $args1, $args2, $args3, $args4 ),
);

$results = new WP_Combine_Queries( $args );

Kelas:

Berikut adalah kelas demo kami:

/**
 * Class WP_Combine_Queries
 * 
 * @uses WP_Query_Empty
 * @link https://stackoverflow.com/a/23704088/2078474
 *
 */

class WP_Combine_Queries extends WP_Query 
{
    protected $args    = array();
    protected $sub_sql = array();
    protected $sql     = '';

    public function __construct( $args = array() )
    {
        $defaults = array(
            'sublimit'       => 1000,
            'posts_per_page' => 10,
            'paged'          => 1,
            'args'           => array(),
        );

        $this->args = wp_parse_args( $args, $defaults );

        add_filter( 'posts_request',  array( $this, 'posts_request' ), PHP_INT_MAX  );

        parent::__construct( array( 'post_type' => 'post' ) );
    }

    public function posts_request( $request )
    {
        remove_filter( current_filter(), array( $this, __FUNCTION__ ), PHP_INT_MAX  );

        // Collect the generated SQL for each sub-query:
        foreach( (array) $this->args['args'] as $a )
        {
            $q = new WP_Query_Empty( $a, $this->args['sublimit'] );
            $this->sub_sql[] = $q->get_sql();
            unset( $q );
        }

        // Combine all the sub-queries into a single SQL query.
        // We must have at least two subqueries:
        if ( count( $this->sub_sql ) > 1 )
        {
            $s = '(' . join( ') UNION (', $this->sub_sql ) . ' ) ';

            $request = sprintf( "SELECT SQL_CALC_FOUND_ROWS * FROM ( $s ) as combined LIMIT %s,%s",
                $this->args['posts_per_page'] * ( $this->args['paged']-1 ),
                $this->args['posts_per_page']
            );          
        }
        return $request;
    }

} // end class

/**
 * Class WP_Query_Empty
 *
 * @link https://stackoverflow.com/a/23704088/2078474
 */

class WP_Query_Empty extends WP_Query 
{
    protected $args      = array();
    protected $sql       = '';
    protected $limits    = '';
    protected $sublimit  = 0;

    public function __construct( $args = array(), $sublimit = 1000 )
    {
        $this->args     = $args;
        $this->sublimit = $sublimit;

        add_filter( 'posts_clauses',  array( $this, 'posts_clauses' ), PHP_INT_MAX  );
        add_filter( 'posts_request',  array( $this, 'posts_request' ), PHP_INT_MAX  );

        parent::__construct( $args );
    }

    public function posts_request( $request )
    {
        remove_filter( current_filter(), array( $this, __FUNCTION__ ), PHP_INT_MAX );
        $this->sql = $this->modify( $request );             
        return '';
    }

    public function posts_clauses( $clauses )
    {
        remove_filter( current_filter(), array( $this, __FUNCTION__ ), PHP_INT_MAX  );
        $this->limits = $clauses['limits'];
        return $clauses;
    }

    protected function modify( $request )
    {
        $request = str_ireplace( 'SQL_CALC_FOUND_ROWS', '', $request );

        if( $this->sublimit > 0 )
            return str_ireplace( $this->limits, sprintf( 'LIMIT %d', $this->sublimit ), $request );
        else
            return $request;
    }

   public function get_sql( )
    {
        return $this->sql;
    }

} // end class

Anda kemudian dapat menyesuaikan kelas dengan kebutuhan Anda.

Saya menggunakan trik disebutkan di sini untuk mempertahankan urutan UNION sub kueri. Anda dapat memodifikasinya sesuai dengan sublimit kami parameter.

Ini juga harus berfungsi untuk kueri utama , dengan menggunakan posts_request filter, misalnya.

Saya harap ini membantu.