MySQL-根据日期加入 [英] MySQL - Join Based on Date

问题描述

是否可以基于同一日期而不是时间因素来联接两个表?

Is it possible to join two tables based on the same date, not factoring in time?

类似的东西:

...从任命左加入销售 subscriptions.date = sales.date ...

...FROM appointments LEFT JOIN sales ON appointments.date = sales.date...

唯一的问题是它是日期时间字段，所以我想确保它只查看日期而忽略时间

The only problem is it is a datetime field, so I want to make sure it is only looking at the date and ignoring time

推荐答案

您可以这样做:

FROM appointments
LEFT JOIN sales ON DATE(appointments.date) = DATE(sales.date)

但是我很确定它将无法使用索引，因此会非常慢.

But I'm pretty sure it won't be able to use an index, so will be very slow.

最好在每个表中添加一个日期列.

You might be better off adding a date column to each table.

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