特殊条件不满意时如何插入表格

Question

I want to insert into table shp_postmetawhen it does not have the meta_key = '_thumbnail_id'.

The inserted value is from the same table shp_postmeta where meta_key = '_product_image_gallery' i.e. in form of sql statement

SELECT meta_key, meta_value FROM shp_postmeta WHERE meta_key = '_product_image_gallery'

This table is related to a different table shp_post where shp_posts.ID = shp_postmeta.post_id

The table structure of shp_postmeta is:

meta_id | post_id | meta_key | meta_value

Table structure of shp_posts table is:

ID | post_author | ....

These are WordPress table structure.

EDIT 1

In WP there are some woocommerce product which does not have featured image but they have product gallery images. Images are uploaded into the media.So I wanted to make the gallery image to featured image to which products those do not have featured image. Products are in large amount. So I wanted to automate it through script.

Answer 1

Because shp_postmeta has an auto_increment PK you can execute:

INSERT INTO shp_postmeta 
  SELECT null, p1.post_id, '_thumbnail_id', p1.meta_value 
  FROM shp_postmeta p1
  WHERE p1.post_id NOT IN(
             SELECT p2.post_id 
             FROM shp_postmeta p2 
             WHERE p2.meta_key = '_thumbnail_id')
     AND p1.meta_key = '_product_image_gallery' ;