mysql UNION with COUNT - mysql

Question

I know there are many posts in similar issues to mine, but I do not seem to be able to find an applicable solution to my case, as below.
I have added null columns so that the number of columns match and I know that I need to have all columns stated in the first select. Therein lies the problem. I do not know how to include a COUNT column in the first select that would correspond to the COUNT in the second select.
Thanks for the assistance.
First select:
SELECT brands.brand_id,
brands.brand,
models.model_id,
models.model,
segments.segment_id,
segments.segment,
versions.version_id,
versions.version,
versions.places,
versions.gearbox,
versions.doors,
prices.price
FROM versions
INNER JOIN models USING (model_id)
INNER JOIN segments USING (segment_id)
INNER JOIN brands USING (brand_id)
INNER JOIN prices USING(version_id)
WHERE price BETWEEN 200001 AND 225000
AND brands.active = 'Y'
AND models.active = 'Y'
AND versions.active = 'Y'
Second select:
SELECT Count(*) AS SafetyItems,
version_id,
NULL AS COL3,
NULL AS ....,
NULL AS COL12
FROM versiontrim
INNER JOIN trims USING(trim_id)
INNER JOIN versions USING(version_id)
INNER JOIN prices USING(version_id)
INNER JOIN models USING (model_id)
INNER JOIN brands USING (brand_id)
WHERE trimtype IN( 'sec', 'help' )
AND price BETWEEN 200001 AND 225000
AND brands.active = 'Y'
AND models.active = 'Y'
AND versions.active = 'Y'
GROUP BY version_id
Sample result of first select:
brand_id brand model_id model segment_id version_id price
58 Renault 11 Megane 4 44 209900
58 Renault 14 Scenic 5 54 209900
58 Renault 11 Megane 4 69 200900
71 Toyota 29 Yaris 2 214 200900
71 Toyota 30 Auri 4 216 207900
52 Nissan 58 Pick-up 14 282 209000
24 Ford 21 Focus 4 290 209000
Sample result of second select that I want have appended to above ( after the price column):
SafetyItems version_id
9 44
7 54
9 69
10 214
6 216
1 282
10 290

Answer 1

I guess you also want to put a NULL column in your first SELECT statement that would correspond for the COUNT column in the second SELECT statement.
Just put a NULL column in your first SELECT just like in your second SELECT statement, that should be fine. And do not forget the ALIAS of the column, since UNION uses the column name of the first SELECT.
SELECT
NULL AS SafetyItems,
brands.brand_id,
brands.brand,
models.model_id,
models.model,
segments.segment_id,
segments.segment,
versions.version_id,
versions.version,
versions.places,
versions.gearbox,
versions.doors,
prices.price
FROM versions
INNER JOIN models
USING (model_id)
INNER JOIN segments
USING (segment_id)
INNER JOIN brands
USING (brand_id)
INNER JOIN prices
USING(version_id)
WHERE price BETWEEN 200001 AND 225000
AND brands.active='Y'
AND models.active='Y'
AND versions.active='Y'
But then, you need to add another NULL column in the second SELECT to match with column count in the first SELECT. Hope this will help you.

Answer 2

I realized I was going about this with the wrong approach. Initially I thought I could not do select 2 with COUNT as part of select 1. It turns out it is possible and I managed to have it done after some struggling.
Thanks for the input. Please see solution below:
SELECT brands.brand_id,
brands.brand,
models.model_id,
models.model,
segments.segment_id,
segments.segment,
versions.version_id,
versions.version,
versions.places,
versions.gearbox,
versions.doors,
prices.price,
COUNT(trimtype)
FROM versions
INNER JOIN models USING (model_id)
INNER JOIN segments USING (segment_id)
INNER JOIN brands USING (brand_id)
INNER JOIN prices USING(version_id)
INNER JOIN versiontrim USING(version_id)
INNER JOIN trims USING(trim_id)
WHERE price BETWEEN 200001 AND 210000
AND trimtype IN('sec', 'help')
AND brands.active = 'Y'
AND models.active = 'Y'
AND versions.active = 'Y'
GROUP BY version_id