如果您使用的是Wordpress 4.2或更新版本，则可以执行以下操作：

$args = array( 
    \'post_type\'       => \'products\',
    \'posts_per_page\'  => 10,
    \'meta_query\'      => array(
        \'relation\'    => \'AND\',
        \'tools_clause\' => array(
            \'key\'     => \'tools\',
            \'compare\' => \'EXISTS\',
        ),
        \'create_date_clause\' => array(
            \'key\'     => \'create_date\',
            \'compare\' => \'EXISTS\',
        ),
    ),
    \'order_by\' => array(
        \'create_date_clause\' => \'ASC\',
        \'tools_clause\' => \'ASC\',
    )
);

请看这里：Query improvements in WP 4.2: ‘orderby’ and ‘meta_query’

看起来不错。在我的情况下，应该是这样的：

$args = array( 
\'post_type\'       => \'products\',
\'posts_per_page\'  => 10,
\'meta_query\'      => array(
    \'tools_clause\' => array(
        \'key\'     => \'producttype\',
        \'value\'     => \'tools\',
        \'compare\' => \'EXISTS\',
    ),
),
\'order_by\' => array(
    \'date\' => \'ASC\',
    \'tools_clause\' => \'ASC\',
));

但有了这一点，我只能得到带有producttype“tools”的产品。但我需要先获得所有其他产品类型，然后是“工具”。