MySQL 8.0

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CREATE TABLE Table1 (id INT,status VARCHAR(50));

INSERT INTO Table1 (id,status) 
VALUES
(1,'active'),
(2,'active'),
(3,'away');
-- Tab2 simulates the view.

CREATE TABLE Table2 (id INT,session INT, rand1 VARCHAR(50));

INSERT INTO Table2 (id,session,rand1) 
VALUES
(1,1,'BRK'),
(1,2,'GOOG'),
(2,1,'HOG'),
(2,2,'XOM'),
(3,1,'INTC'),
(3,2,'MSFT');
CREATE TABLE Table3 (id INT,session VARCHAR(50),rand1 VARCHAR(50));

INSERT INTO Table3 (employee_id,session,rand1) 
VALUES
(1,1,NULL),
(1,2,NULL),
(2,1,NULL),
(2,2,NULL),
(3,1,NULL),
(3,2,NULL);
-- When a row inside Table1.status is UPDATED, then UPDATE Table3.rand1 with value from
-- from Table2.rand1 for same ID. Each ID in Table3 has two rows, both need to
-- be updated.

drop trigger if exists trigger1;
CREATE TRIGGER trigger1
AFTER UPDATE
ON Table1
FOR EACH ROW
BEGIN

CASE WHEN NEW.status <> OLD.status then
UPDATE Table3
SET rand1 = ( SELECT rand1
FROM Table2
where 
-- My attempts at a where clause updated the entire table, rather than just the
-- rows associated to the ID in Table1
limit 1);
end;

end;
UPDATE Table1.status
Set status = 'away'
Where id = 1;


select * from Table1
UPDATE command denied to user 'u_1085559960'@'localhost' for table 'status'