where子句for等于一个字段，不等于另一个

你可以写：

SELECt *  FROM wp_posts  JOIN wp_term_relationships    ON wp_term_relationships.object_id = wp_posts.ID WHERe term_taxonomy_id = 80   AND wp_posts.id NOT IN        ( SELECt object_id FROM wp_term_relationshipsWHERe term_taxonomy_id = 109        );

（见搂13.2.10.3 “与子查询

ANY

IN

SOME