我刚找到原因。这是因为我使用ACF Pro作为积木。数据将以json格式写入数据库，URL将避开所有斜杠和双引号。比如说

src=\\"http:\\/\\/dev.example.com\\/website\\/wp-content\\/uploads\\/2019\\/10\\/identity.jpg\\"

update wp_posts set post_content = replace(post_content,\'http:\\/\\/dev.example.com\\/website\', \'http:\\/\\/www.website.com\');