Odtnhj

I need to get the values from the meta_value column that have "shipping" in the corresponding meta_key column and concatenate them into a comma separated row.

I'm a bit of a noob to SQL so please be gentle.

My current query is this:

SELECT wp_postmeta.post_ID, wp_postmeta.meta_key, wp_postmeta.meta_value, wp_posts.ID, wp_posts.post_status 
FROM wp_postmeta 
CROSS JOIN wp_posts 
WHERE wp_postmeta.post_ID= wp_posts.ID 
 AND wp_posts.post_status LIKE 'wc-processing' 
 AND (wp_postmeta.meta_key LIKE '%shipping%' OR wp_postmeta.meta_key LIKE '_order_total') 

So, here's your query (note how I write it - I find that good formatting of SQL helps to read it):

SELECT 
 wp_postmeta.post_ID, 
 wp_postmeta.meta_key, 
 wp_postmeta.meta_value, 
 wp_posts.ID, 
 wp_posts.post_status 
FROM 
 wp_postmeta 
CROSS JOIN 
 wp_posts 
WHERE 
 wp_postmeta.post_ID = wp_posts.ID 
 AND wp_posts.post_status LIKE 'wc-processing' 
 AND (wp_postmeta.meta_key LIKE '%shipping%' OR wp_postmeta.meta_key LIKE '_order_total') 

Here's what I think you want (you use the MySQL concat function):

Select
 concat(
 wp_postmeta.meta_key, ',',
 wp_postmeta.meta_value
 ) as formatted_row
FROM 
 wp_postmeta 
INNER JOIN 
 wp_posts 
ON
 wp_postmeta.post_ID = wp_posts.ID 
WHERE 
 wp_posts.post_status LIKE 'wc-processing' 
 AND (
 wp_postmeta.meta_key LIKE '%shipping%' 
 OR wp_postmeta.meta_key LIKE '_order_total'
 ) 

Also note: Single quotes and double quotes mean different things in different databases.

You can use GROUP_CONCAT to join the strings together. As has been pointed out by @kermit, you should use an INNER JOIN not a CROSS JOIN. I am presuming you want to keep the order total separate from the shipping details, so you will need to use conditional aggregation as well. This query should do what you want:

SELECT m.post_ID
 , GROUP_CONCAT(CASE WHEN m.meta_key LIKE '%shipping%' THEN m.meta_value END) AS shipping_info
 , MAX(CASE WHEN m.meta_key = '_order_total' THEN m.meta_value ELSE 0 END) AS order_total
FROM wp_postmeta m
INNER JOIN wp_posts p ON m.post_ID = p.ID 
WHERE p.post_status LIKE 'wc-processing' 
 AND (m.meta_key LIKE '%shipping%' OR m.meta_key LIKE '_order_total')

this should do the trick its a bit more involved than on sql server but easy enough

create table if not exists test(col1 varchar(10),col2 varchar(10), col3 varchar(10));
insert into test values("this","is","test");
select concat(col1,",",col2,",",col3) as csvCol from test

delivers

csvCol
this,is,test