sql内でIF文を２つ使いたい IF(EXISTS(SELECT price FROM price_h WHERE id = Product.price_h_id limit 1), (SELECT price FROM price_h WHERE id = Product.price_h_id limit 1), Product.f_price ) IF`(SELECT price FROM price_h WHERE id = Product.price_h_id limit 1)``Product.f_price`100100,100 IF(EXISTS(SELECT price FROM price_h WHERE id = Product.price_h_id limit 1), IF((SELECT price FROM price_h WHERE id = Product.price_h_id limit 1)<100), 100, (SELECT price FROM price_h WHERE id = Product.price_h_id limit 1), IF(Product.f_price < 100), 100, Product.f_price, ) MySQL5.6

1. price_hproductpriceProduct.f_price
2. <100100



1COALESCENULLIFNULL()


SELECT COALESCE(price_h.price, Product.f_price)
FROM price_h LEFT JOIN Product ON price_h.id = Product.price_h_id


2price<100100,price


SELECT IF(price < 100, 100, price)
FROM price_h





SELECT IF(COALESCE(price_h.price, Product.f_price) < 100,
100,
COALESCE(price_h.price, Product.f_price))
FROM price_h LEFT JOIN Product ON price_h.id = Product.price_h_id