在MySQL中使用较高的值作为变量

Question

Let's say I have 2 tables:

people
cars

Now, lets say these 2 tables both have a column for a unix_timestamp() called date_created

How would I write a query that will create a variable based on whichever of the 2 values is higher? I need this for ordering.

Example (which obviously doesn't work):

select p.name, c.model, higher_value(p.date_created, c.date_created) as higher_date
from `people` as p
left join `cars` as c on (c.id_person = p.id)
order by higher_date desc

Hope this makes sense - any help would be appreciated.

Answer 1

You could always use GREATEST() to get the higher date. Example below:

select p.name, c.model, GREATEST(p.date_created, c.date_created) as higher_date
from `people` as p
left join `cars` as c on (c.id_person = p.id)
order by GREATEST(p.date_created, c.date_created) desc