Table: patients
+-------------+---------+ | Column Name | Type | +-------------+---------+ | patient_id | int | | patient_name| varchar | | age | int | +-------------+---------+ patient_id is the unique identifier for this table. Each row contains information about a patient.
Table: covid_tests
+-------------+---------+ | Column Name | Type | +-------------+---------+ | test_id | int | | patient_id | int | | test_date | date | | result | varchar | +-------------+---------+ test_id is the unique identifier for this table. Each row represents a COVID test result. The result can be Positive, Negative, or Inconclusive.
Write a solution to find patients who have recovered from COVID - patients who tested positive but later tested negative.
Return the result table ordered by recovery_time
in ascending order, then by patient_name
in ascending order.
The result format is in the following example.
Example:
Input:
patients table:
+------------+--------------+-----+ | patient_id | patient_name | age | +------------+--------------+-----+ | 1 | Alice Smith | 28 | | 2 | Bob Johnson | 35 | | 3 | Carol Davis | 42 | | 4 | David Wilson | 31 | | 5 | Emma Brown | 29 | +------------+--------------+-----+
covid_tests table:
+---------+------------+------------+--------------+ | test_id | patient_id | test_date | result | +---------+------------+------------+--------------+ | 1 | 1 | 2023-01-15 | Positive | | 2 | 1 | 2023-01-25 | Negative | | 3 | 2 | 2023-02-01 | Positive | | 4 | 2 | 2023-02-05 | Inconclusive | | 5 | 2 | 2023-02-12 | Negative | | 6 | 3 | 2023-01-20 | Negative | | 7 | 3 | 2023-02-10 | Positive | | 8 | 3 | 2023-02-20 | Negative | | 9 | 4 | 2023-01-10 | Positive | | 10 | 4 | 2023-01-18 | Positive | | 11 | 5 | 2023-02-15 | Negative | | 12 | 5 | 2023-02-20 | Negative | +---------+------------+------------+--------------+
Output:
+------------+--------------+-----+---------------+ | patient_id | patient_name | age | recovery_time | +------------+--------------+-----+---------------+ | 1 | Alice Smith | 28 | 10 | | 3 | Carol Davis | 42 | 10 | | 2 | Bob Johnson | 35 | 11 | +------------+--------------+-----+---------------+
Explanation:
Output table is ordered by recovery_time in ascending order, and then by patient_name in ascending order.