Combining Two SQL Select Queries with Where Clauses - mysql

Question

I have two Oracle queries that I need combined through an inner join where the tables are joined using the person_uid field. This is because I need to compare what an employee's pay, job title, and supervisor was from one year to the next. I need to have the 2015 data and the 2014 data in the same row for each employee, so if this can be done by doing a subquery using an inner join on the person_uid field, that is the method that I believe will accomplish this.
Here is the first query that pulls the necessary 2015 data:
SELECT person_uid,
id ,
position_contract_type,
position,
job_suffix,
position_status,
effective_date,
position_employee_class,
timesheet_organization ,
appointment_pct ,
annual_salary ,
per_pay_salary ,
hourly_rate ,
position_title ,
academic_title ,
supervisor_id ,
supervisor_name ,
supervisor_position ,
supervisor_job_suffix ,
supervisor_title ,
assignment_grade ,
position_change_reason ,
position_change_reason_desc
FROM employee_position_cunm posn
WHERE posn.position_contract_type = 'P'
AND posn.position_status <> 'T'
AND posn.effective_date = (SELECT MAX(effective_date)
FROM employee_position_cunm p2
WHERE p2.person_uid = posn.person_uid
AND p2.position = posn.position
AND p2.job_suffix = posn.job_suffix
AND p2.effective_date <= '01-Nov-2015')
order by person_uid
I need it to be joined to this query on the person_uid field so that each unique ID for the employee has the records for both years in a single row:
SELECT person_uid,
id ,
position_contract_type,
position,
job_suffix,
position_status,
effective_date,
position_employee_class,
timesheet_organization ,
appointment_pct ,
annual_salary ,
per_pay_salary ,
hourly_rate ,
position_title ,
academic_title ,
supervisor_id ,
supervisor_name ,
supervisor_position ,
supervisor_job_suffix ,
supervisor_title ,
assignment_grade ,
position_change_reason ,
position_change_reason_desc
FROM employee_position_cunm posn
WHERE posn.position_contract_type = 'P'
AND posn.position_status <> 'T'
AND posn.effective_date = (SELECT MAX(effective_date)
FROM employee_position_cunm p2
WHERE p2.person_uid = posn.person_uid
AND p2.position = posn.position
AND p2.job_suffix = posn.job_suffix
AND p2.effective_date <= '01-Nov-2014')
order by person_uid

Answer 1

An easy way would be to use OR:
WHERE posn.position_contract_type = 'P' AND
posn.position_status <> 'T' AND
(posn.effective_date = (SELECT MAX(effective_date)
FROM employee_position_cunm p2
WHERE p2.person_uid = posn.person_uid
p2.position = posn.position AND
p2.job_suffix = posn.job_suffix AND
p2.effective_date <= '01-Nov-2014'
) OR
posn.effective_date = (SELECT MAX(effective_date)
FROM employee_position_cunm p2
WHERE p2.person_uid = posn.person_uid
p2.position = posn.position AND
p2.job_suffix = posn.job_suffix AND
p2.effective_date <= '01-Nov-2015'
)
)

Answer 2

In Oracle you could do a UNION or a UNION ALL.
SELECT person_uid,
id ,
position_contract_type,
position,
job_suffix,
position_status,
effective_date,
position_employee_class,
timesheet_organization ,
appointment_pct ,
annual_salary ,
per_pay_salary ,
hourly_rate ,
position_title ,
academic_title ,
supervisor_id ,
supervisor_name ,
supervisor_position ,
supervisor_job_suffix ,
supervisor_title ,
assignment_grade ,
position_change_reason ,
position_change_reason_desc
FROM employee_position_cunm posn
WHERE ...
...
...
UNION ALL
SELECT person_uid,
id ,
position_contract_type,
position,
job_suffix,
position_status,
effective_date,
position_employee_class,
timesheet_organization ,
appointment_pct ,
annual_salary ,
per_pay_salary ,
hourly_rate ,
position_title ,
academic_title ,
supervisor_id ,
supervisor_name ,
supervisor_position ,
supervisor_job_suffix ,
supervisor_title ,
assignment_grade ,
position_change_reason ,
position_change_reason_desc
FROM employee_position_cunm posn
WHERE ....
....
....;