根据Mysql同一行中的另一个值减去值

Question

I have a table with following date and value. I need to subtract the values based on the date[max date value - min date value] and create a table.

   date    value
2014-11-07 229275
2014-11-24 138746
2014-12-17 127112

The intended output is:

maxdate    mindate     value
2014-12-17 2014-11-07 102163

Answer 1

If you could use max(value) and min(value), then it would be easy:

select max(date) as maxdate, min(date) as mindate, max(value) - min(value)
from table;

This happens to work for your example.

Assuming you really want the value on the min date and on the max date, try this instead:

select maxt.date as maxdate, mint.date as mindate, (mint.value - maxt.value) as diff
from (select t.* from table t order by date limit 1) as mint cross join
     (select t.* from table t order by date desc limit 1) as maxt;