Question

我正在建立库存管理系统，目前我正致力于报告功能。我想查询在给定日期之前每天销售的产品总数。查询：

SELECT created_at as created_at, SUM(quantity) as product_sales
FROM sales_products
WHERE created_at > '2018-04-19'
GROUP BY created_at
ORDER BY created_at DESC
LIMIT 100;

输出：

"created_at"    "product_sales"
"2018-05-01 09:41:51"   "110"
"2018-05-01 09:41:11"   "150"
"2018-05-01 09:40:57"   "120"
"2018-04-29 16:25:50"   "12"
"2018-04-25 11:54:26"   "2385"
"2018-04-24 11:54:26"   "2485"
"2018-04-23 11:54:26"   "2278"
"2018-04-22 11:54:26"   "2277"
"2018-04-21 11:54:26"   "2330"
"2018-04-20 11:54:26"   "2408"
"2018-04-19 11:54:26"   "2425"

现在直到今天，我插入了更多的值，总和发生了我想要的方式。但是，时间戳略有不同的记录不会分组。我也尝试使用LEFT（created_at，10）来仅选择日期部分，但它不起作用。

有什么想法吗？

非常感谢你！

SELECT LEFT(created_at, 10) as created, SUM(quantity) as product_sales
FROM sales_products
WHERE created_at > '2018-04-19'
GROUP BY created_at
ORDER BY created_at DESC
LIMIT 100;

Answer 1

要按天分组，请使用group by date(created_at)：

select date(created_at) as day, sum(quantity) as product_sales 
from sales_products
where created_at > '2018-04-19'
group by day
order by day desc
limit 100

date函数从表达式中提取日期并丢弃一天中的时间，这可能会因您的记录而异。

Answer 2

这应该有所帮助：

select cast(created_at as date) as Day, sum(quantity) as product_sales 
from sales_products
where created_at > '2018-04-19'
group by Day
order by Day desc
limit 100

通过时间戳进行SQL分组会产生意外结果

2 个答案: