Merge two rows in mysql database table with condition

Question

I have table in mysql database and in that table I do some query to display result from the table. But I want to merge some row in my table.

This is the structure and example value of my table.

id | benefit | plan_day | price
-------------------------------
1 | Free Pick up | 100 | 540
2 | Free Tea | 100 | 540

That example have same value in plan_day but different value in benefit .

This is my second example with different in plan_day and benefit

id | benefit | plan_day | price
-------------------------------
1 | Free Pick up | 110 | 540
2 | Free Tea | 100 | 540

What I want to know is I want to merge that two rows with condition if the value in plan_day is the same I just want merge benefit and the price is not SUM but if plan_day have different value I want to merge benefit and that plan_day itself and I want to SUM the price .

This is result I want to display :

Condition if plan_day have same value.

Free Pick up, Free Tea | 100 | 540

Condition if plan_day have different value.

Free Pick up, Free Tea | 110, 100 | 1080

And this is what I have been do but not success.

SELECT GROUP_CONCAT(benefit SEPARATOR ',') AS benefit, GROUP_CONCAT(plan_day SEPARATOR ',') AS plan_day, SUM(price) as price
FROM special_offer

Anyone can help me with this issue ? Thank you.

Answer 1

Just add the DISTINCT clause to your query:

SELECT
  GROUP_CONCAT(DISTINCT benefit SEPARATOR ',') AS benefit,
  GROUP_CONCAT(DISTINCT plan_day SEPARATOR ',') AS plan_day,
  SUM(price) as price
FROM
  special_offer

Answer 2

I think you want this:

select plan_day,
    group_concat(benefit order by id separator ',') benefits,
    max(price) price
from t
group by plan_day
having count(*) > 1

union all

select *
from (
    select group_concat(t1.plan_day order by t1.id separator ',') plan_day,
        group_concat(t1.benefit order by t1.id separator ','),
        sum(t1.price) price
    from t t1
    join (
        select plan_day
        from t
        group by plan_day
        having count(*) = 1
        ) t2 on t1.plan_day = t2.plan_day
    )
where plan_day is not null;

For this data:

(1, 'Free Pick up', 110, 540 ),
(2, 'Free Tea',     100, 540 );

Produces:

110,100     Free Pick up,Free Tea   1080

And for data

(1, 'Free Pick up', 100, 540 ),
(2, 'Free Tea',     100, 540 );

Produces:

100         Free Pick up,Free Tea   540