Question

我有查询工作正常，但现在数据是数百万，所以获取它说服务器找不到。我想在这里比较上个月的当月和上月的客户明智的销售情况，以便我按user_id用户分组。

我看到通过查询删除组运行得更快，但输出我只希望客户明智，所以它必须在那里。

SELECT Customer.id, 
       Customer.first_name, 
       Customer.last_name, 
       SUM(Sale.`cal_qty`) AS totPurchase, 
       Sale2.tot2 as totPurchase2 
FROM `customers` AS Customer 
LEFT JOIN `sales` AS Sale 
    ON Sale.customer_id = Customer.id 
LEFT JOIN (
    SELECT s2.customer_id AS customer_id, 
           SUM(s2.cal_qty) as tot2 
    FROM sales as s2 
    WHERE s2.sale_date between '2015-07-23' 
        AND '2015-08-21' 
    GROUP BY s2.customer_id 
) AS Sale2 
    ON Sale.customer_id = Sale2.customer_id 
WHERE Sale.sale_date between '2015-08-22' AND '2015-09-21' 
GROUP BY Sale.`customer_id` 
having totPurchase > totPurchase2 
ORDER BY totPurchase DESC

任何人都可以建议我对查询进行优化查询。

提前致谢。

Answer 1

不确定，但您可以尝试以下查询，可能对您有帮助 -

注意：假设customer.id是主键或索引，sale.customer_id也被编入索引，sale.sale_date也被编入索引。

SELECT Customer.id, 
       Customer.first_name, 
       Customer.last_name, 
       sale1.totPurchase, 
       Sale2.tot2 AS totPurchase2 
FROM `customers` AS Customer 
JOIN 
(
SELECT Sale.`customer_id`,
       SUM(Sale.`cal_qty`) AS totPurchase 
FROM `sales` AS Sale
WHERE Sale.sale_date BETWEEN '2015-08-22' AND '2015-09-21' 
GROUP BY Sale.`customer_id` 
) AS Sale1 ON Sale1.customer_id = Customer.id 
LEFT JOIN 
(
    SELECT s2.customer_id AS customer_id, 
           SUM(s2.cal_qty) AS tot2 
    FROM sales AS s2 
    WHERE s2.sale_date BETWEEN '2015-07-23' 
        AND '2015-08-21' 
    GROUP BY s2.customer_id 
) AS Sale2 
ON Sale1.customer_id = Sale2.customer_id 
HAVING totPurchase > totPurchase2 
ORDER BY totPurchase DESC

在retrive时需要有关查询优化的帮助，找不到错误服务器

1 个答案: