MySQL按日期获取最接近的值

Question

I have following table where I store the customer counts every week

| area    | date       | count |
|---------|------------|-------|
| AREA I  | 2016-03-20 | 530   |
| AREA I  | 2016-03-13 | 520   |
| AREA II | 2016-03-20 | 370   |

Now I want to get the nearest customer count by date value at another table. So if I give f.ex. date 2016-03-15 it should return 520 for AREA I and 370 for AREA II .

Example query:

SELECT a.period, a.area, b.customerCount FROM periods a
JOIN customer_count b ON (...)
GROUP BY a.period, a.area

I think that I should be using ABS() and DATEDIFF() somehow but I didn't get that. Or is there some other way to do this?

Thanks in advance.

Answer 1

Try to use:

SELECT a.period, a.area, b.customerCount FROM periods a
JOIN customer_count b ON (...)
GROUP BY a.period, a.area
ORDER BY ABS(DATEDIFF( `date`, NOW()))