SQL計數，但排除某些行

Question

我正在計數提交職位查詢：

SELECT COUNT(*) 
FROM `wp_posts` 
WHERE `post_author` = 4 
    AND `post_type` = 'nf_sub' 
    AND `post_status` = 'publish' 

這將返回所有職位。現在我想在排除_form_id_ = 1這個查詢職位：

SELECT * 
FROM `wp_postmeta` 
WHERE `post_id` = 225 
    AND `meta_key` = '_form_id' 
    AND `meta_value` = 1 

我怎樣才能將二者結合起來成爲一個查詢只計算行，其中_form_id_不等於1？

Answer 1

從這些表中，假設鏈接字段是wp_posts表中的主鍵wpposts_id。

使用下面的內部查詢，還有其他方法來實現這一點。

SELECT COUNT(*) 
FROM `wp_posts` 
WHERE `post_author` = 4 
    AND `post_type` = 'nf_sub' 
    AND `post_status` = 'publish' 
    and `wppost_id` not in (SELECT `wppost_id` 
          from `wp_postmeta` 
          WHERE `post_id` = 225 
           AND `meta_key` = '_form_id' 
           AND `meta_value` = 1 
         ); 

Answer 2

這就是答案。感謝所有提供線索的人。

SELECT COUNT(*) FROM `wp_posts` WHERE `post_author` = ".get_current_user_id()." AND `post_type` = 'nf_sub' AND `post_status` = 'publish' AND `ID` NOT IN (SELECT `post_id` FROM `wp_postmeta` WHERE `meta_key` = '_form_id' AND `meta_value` = 1)