Some MySQL Querys which you need by the programming with php / mysql or  magento:

MySQL Update with sub-select: Update a value of an option, e.g. „price“, where option-name is like „optionname“

UPDATE catalog_product_option_type_price t1
SET t1.price='30'
WHERE t1.option_type_id in (SELECT option_type_id FROM catalog_product_option_type_title WHERE `title` like '%optionname%');

Other example with an own table where are not all product_id’s imported and must be updated by sku

UPDATE mypharmacy_stock_statistical_data t2,
(   SELECT entity_id,sku
    FROM catalog_product_entity
) t1
SET t2.product_id = t1.entity_id
WHERE t1.sku=t2.sku

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