Question

我正在尝试计算日期范围内的订单数量，按日期分组，但也计算在同一日期发生的其他记录。

我的查询看起来像这样：

SELECT 
order_date,
DATE_FORMAT(order_date,'%W') AS day, 
DATE_FORMAT(order_date,'%d-%m-%Y') AS orderdate, 
COUNT(orderID) As orders, 
a.something AS something
b.something AS something_else,
a.something + b.something AS total_somethings
FROM orders,
(SELECT COUNT(*) AS something FROM other_table) AS a,
(SELECT COUNT(*) AS something FROM another_table) AS b,
GROUP BY order_date 
HAVING order_date >= '2014-01-01' AND order_date <= '2014-01-31' 
ORDER BY order_date ASC

它工作正常，但很明显，子查询计算每一行。表'other_table'和'another_table'都有日期字段，我想用它来限制每行的结果。

我尝试将子查询更改为：

(SELECT COUNT(*) AS something FROM other_table WHERE date_field = order_date) AS a,

但它仍在计算每一行。

任何建议表示赞赏。

由于

Answer 1

在以下查询中，我将date_field分组在other_table和another_table表中。然后，我使用orders加入了date_field表。以下查询是否适合您？

SELECT 
order_date,
DATE_FORMAT(order_date,'%W') AS day, 
DATE_FORMAT(order_date,'%d-%m-%Y') AS orderdate, 
COUNT(orderID) As orders, 
a.something AS something
b.something AS something_else,
a.something + b.something AS total_somethings
FROM orders,
(SELECT date_field, COUNT(*) AS something FROM other_table GROUP BY date_field) AS a,
(SELECT date_field, COUNT(*) AS something FROM another_table GROUP BY date_field) AS b
WHERE order_date >= '2014-01-01' AND order_date <= '2014-01-31' 
AND order_date = a.date_field AND order_date = b.date_field
GROUP BY order_date 
ORDER BY order_date ASC;

MySQL GROUP BY与子查询（ies）

1 个答案: