My problem is the following update, which I'm going to make a routine for phpmyadmin.I’ll put a few screenshots of the tables I’m querying.
[wp\_postmeta Sku](https://i.stack.imgur.com/03IsL.png)

[wp\_postmeta Stock](https://i.stack.imgur.com/RAjd2.png)

Here is also an example of a SELECT query that combines tables with each other.
[SELECT higher stock](https://i.stack.imgur.com/1dXlA.png)
The SELECT query works but I haven't been able to change it to an UPDATE query.
SELECT
´´´

```
BEGIN
SELECT wp_posts.ID ,wp_posts.post_title 
AS Name ,wstock.meta_value 
AS Stock ,wsku.meta_value 
AS SKU FROM wp_posts 
LEFT JOIN wp_postmeta 
AS wstock ON wp_posts.ID = wstock.post_id 
and wstock.meta_key='_stock' 
LEFT JOIN wp_postmeta 
AS wsku ON wp_posts.ID = wsku.post_id 
AND wsku.meta_key='_sku' 
WHERE post_type = 'product' 
AND wstock.meta_value != 100 
AND wstock.meta_value IS NOT NULL
AND wstock.meta_value > Saldo
AND wsku.meta_value = SKU;
END

```

´´´
The ID comes from another table which links Sku and Stock.

I have been desperately trying various examples of the work on an UPDATE query,
which would update the online store inventory balance.

```
´´´

 BEGIN
    UPDATE 
            (
            SELECT 
                wp_posts.ID ,
                wp_posts.post_title AS Name ,
                wstock.meta_value AS Stock ,
                wsku.meta_value AS SKU 
            FROM wp_posts 
                LEFT JOIN wp_postmeta AS wstock 
                ON wp_posts.ID = wstock.post_id 
                AND wstock.meta_key='_stock' 
                LEFT JOIN wp_postmeta AS wsku 
                ON wp_posts.ID = wsku.post_id 
            )
        SET wstock.meta_value = Saldo 

          WHERE     
                (
                post_type = 'product' 
                AND wsku.meta_key='_sku' 
                AND wstock.meta_value != 100 
                AND wstock.meta_value IS NOT NULL 
                AND wstock.meta_value != 0
                AND wsku.meta_value = SKU
                AND wstock.meta_value > Saldo
                );
END

´´´

```

It's what I understand the tests that I have completed that the fault lies in a SELECT selection of UPDATE query. I have tried to change it, but I have not found yet functional form.

Stock = Saldo

Test values:
ID: Name: Stock: Sku:
4104 Dynacore D-2S 4 10070

I have tried to debug it in those values just to run SQL in phpmyadmin window.