我正在使用wordpress,我想将数据从一个自定义字段复制到另一个自定义字段。
以下是该表的直观表示形式:
post_id meta_key meta_value
7 shortcode example text
7 video_url
20 shortcode sample text
20 video_url
我想将短代码的meta_value复制到video_url的meta_value,如果他们的post_id匹配
这是我到目前为止所拥有的,但我收到语法错误:
UPDATE wp_postmeta
SET
meta_value = newdata.meta_value
FROM
(
SELECT
post_id,
meta_value
FROM wp_postmeta
WHERE
meta_key = 'shortcode'
) newdata
WHERE
meta_key = "video_url"
AND
post_id = newdata.post_id
这是我收到的错误:
#1064 - You have an error in your SQL syntax; check the manual that
corresponds to your MySQL server version for the right syntax to use near
'FROM
(
SELECT
post_id,
meta_value
FROM wp_postme' at line 4
更新数据时可以使用联接
UPDATE wp_postmeta old
INNER JOIN wp_postmeta new ON old.post_id = new.post_id
SET old.meta_value = new.meta_value
WHERE old.meta_key = 'video_url' AND new.meta_key = 'shortcode';