UNION query results in a new row instead of new column - mysql

Question

The following query returns a result with 5 columns (
date ,lowest_hr_price ,max_hr_price ,min_price , max_price )
instead of
(date ,lowest_hr_price ,max_hr_price , min_price ,max_price , AvgPrice, AvgPieces ).
AvgPrice and AvgPieces are instead added as rows .
(select date(m.min_max_date) as date,
max(case when m.lbl='min_hr_price' then m.min_max_hr_price else null end) as lowest_hr_price,
max(case when m.lbl='max_hr_price' then m.min_max_hr_price else null end) as max_hr_price,
max(case when n.lbl='min_price' then n.min_max_price else null end) as min_price,
max(case when n.lbl='max_price' then n.min_max_price else null end) as max_price
from (select 'min_hr_price' as lbl, price as min_max_hr_price, date_time as min_max_date
from mytable
where date_time in (select min(date_time) as min_date from mytable group by date(date_time)) and symbol = 'dollar'
UNION
select 'max_hr_price', price, date_time
from mytable WHERE symbol = 'dollar'
AND date_time in (select max(date_time) as max_date from mytable WHERE symbol = 'dollar' group by date(date_time))) as m,
(
select 'min_price' as lbl,
min(date_time) as min_max_date,
min(price) as min_max_price
from mytable
WHERE symbol = 'dollar'
group by date(date_time)
UNION
select 'max_price' as lbl,
max(date_time) as min_max_date,
max(price) as min_max_price
from mytable
WHERE symbol = 'dollar'
group by date(date_time)
) n
where m.min_max_date=n.min_max_date
group by date(m.min_max_date)
order by m.min_max_date DESC
)
UNION
(SELECT null, null, date_time, avg (price) as AvgPrice, avg (pieces) as AvgPieces FROM mytable
WHERE symbol = 'dollar'
group by date(date_time))
Actual result:
date |lowest_hr_price | max_hr_price | min_price | max_price
------------------------------------------------------------------------------------
2018-03-06 | 1 | 2 | 0 | 10
NULL | NULL | {date} | {avgprice} | {avgpieces}
Expected result:
date |lowest_hr_price | max_hr_price | min_price | max_price | AvgPrice | AvgPieces
-------------------------------------------------------------------------------------------------------------
2018-03-06 | 1 | 2 | 0 | 10 | {avgprice}| {avgpieces}

Answer 1

if you instead of an union (select rows append one select to each others ) need all the result on the same rows
in this case you could use a cross join eg :
select distinct * from (
(select date(m.min_max_date) as date,
max(case when m.lbl='min_hr_price' then m.min_max_hr_price else null end) as lowest_hr_price,
max(case when m.lbl='max_hr_price' then m.min_max_hr_price else null end) as max_hr_price,
max(case when n.lbl='min_price' then n.min_max_price else null end) as min_price,
max(case when n.lbl='max_price' then n.min_max_price else null end) as max_price
from (select 'min_hr_price' as lbl, price as min_max_hr_price, date_time as min_max_date
from mytable
where date_time in (select min(date_time) as min_date from mytable group by date(date_time)) and symbol = 'dollar'
UNION
select 'max_hr_price', price, date_time
from mytable WHERE symbol = 'dollar'
AND date_time in (select max(date_time) as max_date from mytable WHERE symbol = 'dollar' group by date(date_time))) as m,
(
select 'min_price' as lbl,
min(date_time) as min_max_date,
min(price) as min_max_price
from mytable
WHERE symbol = 'dollar'
group by date(date_time)
UNION
select 'max_price' as lbl,
max(date_time) as min_max_date,
max(price) as min_max_price
from mytable
WHERE symbol = 'dollar'
group by date(date_time)
) n
where m.min_max_date=n.min_max_date
group by date(m.min_max_date)
order by m.min_max_date DESC
) ) T1 INNER join
(SELECT null, null, date_time, avg (price) as AvgPrice, avg (pieces) as AvgPieces FROM mytable
WHERE symbol = 'dollar'
group by date(date_time)) T2 ON date(T1.date) = date(T2.date_time)