存在する場合は1つの値を選択し、存在しない場合は別の値を選択します

1つのアプローチは、catalog_product_entity_textに2回左結合することです。 ID 0用に1回、ID 3用にもう1回、選択したものでCOALESCEを実行します

SELECT
..
 COALESCE(`short_description_id`.`value` , `short_description_id_DEFAULT`.`value`) AS `short_description`
..
FROM 
...

     LEFT JOIN `catalog_product_entity_text` AS `short_description_id` 
     ON p2c.product_id = short_description_id.entity_id 
         AND short_description_id.attribute_id = 62
         AND (short_description_id.store_id = 3)

     LEFT JOIN `catalog_product_entity_text` AS `short_description_id_DEFAULT` 
     ON p2c.product_id = short_description_id.entity_id 
         AND short_description_id.attribute_id = 62
         AND (short_description_id.store_id = 0)