Mysql 区分一列但不是每一列

Question

I have a table (a list of cars, years and models) and I am trying to show a list of just the years, but the list of years that manufacture has made a car could be huge. Meaning when I query "Volvo" Im returning a list of all years Volvo has made a car, Using:

"SELECT id, year FROM `models_auto` WHERE `make`=? ORDER BY `year` DESC;"

However, Volvo may have made 50 cars that year and the return is all 50 duplicate years. I want to return just unique list of years, not duplicates. I looked at DISTINCT but using:

"SELECT DISTINCT id, year FROM `models_auto` WHERE `make`=? ORDER BY `year` DESC;"

Still returns everything because ID is unique. How can I only DISTINCT year?

Thank you.

Answer 1

If you want only the years then you can use use GROUP BY .

SELECT `year`
FROM `models_auto`
WHERE `make`=? 
GROUP BY `year`
ORDER BY `year` DESC;"

Or using DISTINCT :

SELECT DISTINCT `year`
FROM `models_auto`
WHERE `make`=? 
ORDER BY `year` DESC;"

Answer 2

One option is to return the years as a comma delimited list, using group_concat() :

select make, group_concat(distinct year order by year)
from models_auto
group by make;