Updating and Selecting from the same table in MySQL

Question

Have a look at my sqlfiddle:

http://sqlfiddle.com/#!9/60ffc4 (edited)

Code I am trying to execute:

UPDATE inventory SET 
    product_name = CONCAT((SELECT name FROM products_and_packaging 
    WHERE product_id = (SELECT product_id FROM inventory 
    WHERE inventory_id = 196)), ' 100g Bunch')
WHERE inventory_id = 196

The result I am looking for is for product_name in the inventory table is renamed from NULL to "Flowers 100g Bunch" where product_id = 196.

I get the #1093 error (You can't specify target table 'inventory' for update in FROM clause)

Note there are answers to similar questions here: You can't specify target table for update in FROM clause

MySQL Error 1093 - Can't specify target table for update in FROM clause

However I tried to apply those solutions and came up with the exact same error due to the Inner Joins that were suggested. Any pointers in the right direction would be great.

Answer 1

You don't need the nested subquery. Just join the two tables as shown in the linked questions.

UPDATE inventory AS i
JOIN products_and_packaging AS pp ON pp.product_id = i.product_id
SET i.product_name = CONCAT(pp.name, ' 100g Bunch')
WHERE i.inventory_id = 196

DEMO