將查詢轉換爲計數行

Question

如何將此查詢轉換爲行數？

SELECT IF(rz_price_grn != 0, rz_price_grn, ROUND(rz_price2 * currencies.`rate`)) AS `ssc_price`, rz_price_grn, rz_price2, IF(price IS NULL, 0, price) AS `goods_price` 
FROM rz_price 
LEFT JOIN currencies ON currencies.`name` = 'USD' 
LEFT JOIN goods ON goods.id = rz_price.`rz_art` 
LEFT JOIN rz_archive ON rz_archive.rz_art = rz_price.rz_art 
WHERE 
rz_archive.rz_art IS NULL 
HAVING ROUND(ssc_price, 2) != ROUND(goods_price, 2) 
LIMIT 500000 

Answer 1

可以這樣工作嗎？

SELECT Count(*) 
FROM rz_price 
LEFT JOIN currencies ON currencies.`name` = 'USD' 
LEFT JOIN goods ON goods.id = rz_price.`rz_art` 
LEFT JOIN rz_archive ON rz_archive.rz_art = rz_price.rz_art 
WHERE 
rz_archive.rz_art IS NULL 
AND (ROUND(IF(rz_price_grn != 0, rz_price_grn, ROUND(rz_price2 * currencies.`rate`)), 2) != ROUND(IF(price IS NULL, 0, price), 2)) 
--LIMIT 500000 

Answer 2

好，

SELECT COUNT(
    SELECT IF(rz_price_grn != 0, rz_price_grn, ROUND(rz_price2 * currencies.`rate`)) AS `ssc_price`, rz_price_grn, rz_price2, IF(price IS NULL, 0, price) AS `goods_price` 
    FROM rz_price 
    LEFT JOIN currencies ON currencies.`name` = 'USD' 
    LEFT JOIN goods ON goods.id = rz_price.`rz_art` 
    LEFT JOIN rz_archive ON rz_archive.rz_art = rz_price.rz_art 
    WHERE 
    rz_archive.rz_art IS NULL 
    HAVING ROUND(ssc_price, 2) != ROUND(goods_price, 2) 
) 

是否行得通？