根据基于多行的日期/时间范围选择记录

Question

I have following table structure

id          date             time            discount
------------------------------------------------------
1         2015-08-10       09:30:00           50%
2         2016-04-15       14:00:00           30%
3         2018-01-25       18:15:00           75%
4         2018-11-19       11:45:00           45%

I want to query this table to find the discount amount on specific date;

expected result;

if I query for a date between 2015-08-10 09:30:00 - 2016-04-15 13:59:59 it should result 50%

for a date between 2016-04-15 14:00:00 - 2018-01-25 18:14:59 , should result 30%

example:

Query to this table for date 2016-01-10 08:00:00 should result 50%

I have searched through SO & Google but couldn't find a solution for my case;

Tried a query for my example like

SELECT * FROM discounts WHERE date<='2016-01-10' AND time<='08:00:00'
ORDER BY date DESC LIMIT 1

but no luck!

Any help is really appreciated.

Answer 1

You could use something like this for your table structure -

SELECT discount FROM discounts WHERE CAST(CONCAT(date, “ “, time) AS DATETIME) BETWEEN “2015-08-10 09:30:00” AND “2016-04-15 13:59:59”

You might be able to get away without casting the values but this will ensure your date and time values are correctly formatted.

However I would suggest storing the date and time values as a single standard datetime value. Is there a reason why you have it as two separate columns?