I'm running this SQL query:
SELECT wp_woocommerce_order_items.order_id As No_Commande FROM wp_woocommerce_order_items LEFT JOIN ( SELECT meta_value As Prenom FROM wp_postmeta WHERE meta_key = '_shipping_first_name' ) AS a ON wp_woocommerce_order_items.order_id = a.post_id WHERE wp_woocommerce_order_items.order_id =2198 And I get this error:
#1054 - Unknown column 'a.post_id' in 'on clause'.
I think my code is pretty simple, but I can't make it right. What am I doing wrong?
2 Answers
You didn't select post_id in the subquery. You have to select it in the subquery like this:
SELECT wp_woocommerce_order_items.order_id As No_Commande FROM wp_woocommerce_order_items LEFT JOIN ( SELECT meta_value As Prenom, post_id -- <----- this FROM wp_postmeta WHERE meta_key = '_shipping_first_name' ) AS a ON wp_woocommerce_order_items.order_id = a.post_id WHERE wp_woocommerce_order_items.order_id =2198 I recognize that the answer works and has been accepted but there is a much cleaner way to write that query. Tested on mysql and postgres.
SELECT wpoi.order_id As No_Commande FROM wp_woocommerce_order_items AS wpoi LEFT JOIN wp_postmeta AS wpp ON wpoi.order_id = wpp.post_id AND wpp.meta_key = '_shipping_first_name' WHERE wpoi.order_id =2198 
