MySQL 8.0

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-- Create table1
CREATE TABLE table1 (
    id INT,
    time TIME,
    status VARCHAR(10)
);
-- Create table2
CREATE TABLE table2 (
    id INT,
    time TIME
);
-- Insert data into table1
INSERT INTO table1 (id, time, status)
VALUES
    (1, '10:00', 'conn'),
    (1, '10:01', 'disconn'),
    (2, '10:02', 'conn'),
    (2, '10:03', 'disconn'),
    (3, '10:04', 'conn');



-- Insert data into table2
INSERT INTO table2 (id, time)
VALUES
    (3, '10:05');

Records: 5  Duplicates: 0  Warnings: 0


SELECT 
    t1.id,
    t1.time AS conn,
    COALESCE(t1_disconn.time, t2.time) AS disconn
FROM table1 t1
LEFT JOIN table1 t1_disconn ON t1.id = t1_disconn.id AND t1_disconn.status = 'disconn'
LEFT JOIN table2 t2 ON t1.id = t2.id
WHERE t1.status = 'conn'
ORDER BY t1.id;


id
conn
disconn


1
10:00:00
10:01:00

2
10:02:00
10:03:00

3
10:04:00
10:05:00