INSERT INTO shop_product_stocks (sku_id ,stock_id ,product_id ,'count')
(SELECT id.b ,product_id.b ,sku.b ,sort.b ,name.b ,image_id.b, price.b ,primary_price.b ,purchase_price.b ,available.b  FROM shop_product_skus b 
    LEFT JOIN shop_product_ostatki_sander c ON c.sku = b.sku  
    LEFT JOIN shop_product_skus a ON a.sku = c.sku
 WHERE shop_product_stocks.stock_id = 1
)
ON DUPLICATE KEY UPDATE
'count' = 'count'.c   

SELECT *  FROM shop_product_skus AS b 
    LEFT JOIN shop_product_ostatki AS c ON c.sku = b.sku  
    LEFT JOIN shop_product_stocks AS a ON a.sku_id = b.id
 WHERE a.stock_id = 1

INSERT INTO shop_product_stocks (sku_id, stock_id ,product_id,count)
(SELECT *  FROM shop_product_ostatki_sander AS b 
    LEFT JOIN shop_product_skus AS c ON c.sku = b.sku  
    LEFT JOIN shop_product_stocks AS a ON a.sku_id = c.id
WHERE c.product_id>0)