SQL , get difference b/w to id's - mysql

Question

I want to get result from two tables:
Table A
create table A
( propertyId int not null
,PRIMARY KEY (propertyId))
Table B
create table B
( Id int not null
, propertyId int
, FOREIGN KEY (propertyId ) REFERENCES A(propertyId))
Now I want to get the result total count id of Table A exist in Table B AND total count id that does not exist in Table B
SELECT COUNT(property.propertyId) AS 'Occupied'
,(
SELECT COUNT(property.propertyId)
FROM property
INNER JOIN agreement ON property.`propertyId` <> agreement.`propertyId`
) AS 'Vacant'
FROM property
INNER JOIN agreement ON property.`propertyId` = agreement.`propertyId`
WHERE agreement.`isActive` = '1'

Answer 1

You can do a Left join to get the proper result.
select
sum (
case when a.propertyId is not null then 1
else 0
end
) as present_cnt,
sum (
case when a.propertyId is null then 1
else 0
end
) as not_present_cnt
from property p
left join agreement a on p.propertyId = a.propertyId
where a.isActive = '1';
left join will fetch data for a.propertyId from agreement corresponding to p.propertyId, if no match found then null

Answer 2

Your solution should be based on this principle, also exemplified in this SQLFiddle:
SELECT count(CASE
WHEN propertyID IS NOT NULL
AND fk_propertyID IS NOT NULL
THEN 1
ELSE NULL
END) 'exist_in_both_tables'
,count(CASE
WHEN propertyID IS NOT NULL
AND fk_propertyID IS NULL
THEN 1
ELSE NULL
END) 'does_not_exist_in_b'
FROM (
SELECT *
FROM tablea a
LEFT JOIN tableb b ON a.propertyID = b.fk_propertyID
UNION
SELECT *
FROM tablea a
RIGHT JOIN tableb b ON a.propertyID = b.fk_propertyID
) result
You need to duplicate your query and use both LEFT and RIGHT joins and UNION the results of those two separate queries to simulate the result of a FULL JOIN.
After simulating this, you need to go over this result set again, by making this a sub-query and then using aggregate functions, COUNT(), along with CASE statements to count how many matches you have in both tables.
Hence, your final queries should look something like this:
SELECT count(CASE
WHEN Property_PropertyID IS NOT NULL
AND Agreement_PropertyID IS NOT NULL
THEN 1
ELSE NULL
END) 'Occupied'
,count(CASE
WHEN Property_PropertyID IS NOT NULL
AND Agreement_PropertyID IS NULL
THEN 1
ELSE NULL
END) 'Vacant'
FROM (
SELECT property.propertyID 'Property_PropertyID'
FROM property
LEFT JOIN agreement ON property.`propertyId` = agreement.`propertyId`
WHERE agreement.`isActive` = '1'
UNION
SELECT agreement.propertyID 'Agreement_PropertyID'
FROM property
RIGHT JOIN agreement ON property.`propertyId` = agreement.`propertyId`
WHERE agreement.`isActive` = '1'
) ResultSet