MySQL 8.0

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CREATE TABLE data(
 irs_number VARCHAR (50),
 mop_up INTEGER,
 ou VARCHAR (50)
)
INSERT INTO data VALUES 
('0001', 1, 'abc'),
('0001', 0, 'abc'),
('0001', 0, 'cde'),
('0001', 0, 'abc'),
('0002', 1, 'abc'),
('0002', 0, 'abc'),
('0003', 0, 'abc'),
('0003', 0, 'xyz')

Records: 8  Duplicates: 0  Warnings: 0


SELECT irs_number, mop_up, ou
FROM data d
WHERE EXISTS (SELECT 1
              FROM data d2
              WHERE d2.irs_number = d.irs_number AND
                    d2.mop_up = 1
             ) AND
     EXISTS (SELECT 1
              FROM data d2
              WHERE d2.irs_number = d.irs_number AND
                    d2.ou <> d.ou
             )
             


irs_number
mop_up
ou


0001
1
abc

0001
0
abc

0001
0
cde

0001
0
abc