Question

我想出了以下查询来返回产品定价数据。这个查询工作正常，但我想知道是否有办法简化/优化它？

该查询提取有关每种产品的产品和定价详情的信息。如果特定产品没有定价详细信息（p_p。pl_id = 2），请加入另一个包含定价明细的查询（p_p。pl_id = 1）。最后按id对所有产品进行分组以获得不同的行。

使用的表格：产品 - 有关产品的一些详细信息，如名称，描述等。 product_pricing（p_p） - 包含每种产品的定价详情。一种产品的记录可能更多，因为产品价格根据订购数量而有所不同

SELECT * FROM (
(
SELECT `products`.*, 
GROUP_CONCAT(p_p.`qty_range` SEPARATOR '|') AS qty_range, 
GROUP_CONCAT(CAST(p_p.`p_price` AS CHAR) SEPARATOR '|') AS price 
FROM `products`
LEFT JOIN `prod_pricing` AS p_p ON p_p.`prod_id` = `products`.`prod_id` 
WHERE `products`.`account_id` = 2
AND p_p.`pl_id` = 2
GROUP BY `products`.`prod_id`
) 
UNION
(
SELECT `products`.*, 
GROUP_CONCAT(p_p.`qty_range` SEPARATOR '|') AS qty_range, 
GROUP_CONCAT(CAST(p_p.`p_price` AS CHAR) SEPARATOR '|') AS price 
FROM `products`
LEFT JOIN `prod_pricing` AS p_p ON p_p.`prod_id` = `products`.`prod_id` 
WHERE `products`.`account_id` = 2
AND p_p.`pl_id` = 1
GROUP BY `products`.`prod_id`
)) AS list
GROUP BY list.`prod_id`

Answer 1

编辑：我想我现在的意思是，试试：

SELECT t.col1, t.col2,  --[more columns from products table]
IF (t.price2 IS NULL, t.price1, t.price2) AS price,
IF (t.price2 IS NULL, t.qty_range1, t.qty_range2) AS qty_range
FROM
    (
    SELECT p.col1, p.col2 , --[more columns from products table]
    GROUP_CONCAT(p_p1.qty_range SEPARATOR '|') AS qty_range1, 
    GROUP_CONCAT(CAST(p_p1.p_price AS CHAR) SEPARATOR '|') AS price1,
    GROUP_CONCAT(p_p2.qty_range SEPARATOR '|') AS qty_range2,
    GROUP_CONCAT(CAST(p_p2.p_price AS CHAR) SEPARATOR '|') AS price2 
    FROM products p
    LEFT JOIN prod_pricing AS p_p1 ON p_p1.prod_id = p.prod_id AND p_p1.pl_id = 1
    LEFT JOIN prod_pricing AS p_p2 ON p_p2.prod_id = p.prod_id AND p_p2.`pl_id` = 2
    GROUP BY p.prod_id) AS t
Having price IS NOT NULL

Answer 2

由于两个UNIONS几乎相同，或许您可以查看CASE

你可以

WHERE `products`.`account_id` = 2
AND `products`.`prod_id`
AND CASE x
    WHEN y THEN
      p_p.`pl_id` = 2
    ELSE
      p_p.`pl_id` = 1

虽然目前尚不清楚您在何处/如何确定是否有定价细节。但是无论什么列确定 x ，它的值都在 y 中。

Answer 3

好的，我终于明白了。我创建了两个临时表t1，t2，它们反映了pl_id = 1和2的数据。接下来我将这些表连接到products表并使用IF条件返回产品，定价来自pl_id = 2和pl_id = 1仅当pl_id = 2的定价时不存在。感谢大家的帮助！

这是查询

SELECT p.*,
IF(t2.pl_id IS NULL,t1.qty_range,t2.qty_range) AS qty_range,
IF(t2.pl_id IS NULL,t1.price,t2.price) AS price
FROM products AS p
LEFT JOIN
(
    SELECT p_p.prod_id,
    GROUP_CONCAT(p_p.qty_range SEPARATOR '|') AS qty_range, 
    GROUP_CONCAT(CAST(p_p.p_price AS CHAR) SEPARATOR '|') AS price 
    FROM prod_pricing AS p_p WHERE p_p.pl_id = 1
    GROUP BY p_p.prod_id
) AS t1 ON t1.prod_id = p.prod_id
LEFT JOIN
(
    SELECT p_p.prod_id,p_p.pl_id,
    GROUP_CONCAT(p_p.qty_range SEPARATOR '|') AS qty_range, 
    GROUP_CONCAT(CAST(p_p.p_price AS CHAR) SEPARATOR '|') AS price 
    FROM prod_pricing AS p_p WHERE p_p.pl_id = 1
    GROUP BY p_p.prod_id
) AS t2 ON t2.prod_id = p.prod_id 
WHERE p.account_id = 2

有没有办法简化以下mysql查询？

3 个答案: