A MySQL script to shuffle around the names in an employee table. Effectively it replaces the first and last names on each row with names randomly chosen from other rows.

RandomiseNames.sql

SET SQL_SAFE_UPDATES = 0;

drop table if exists scramble;
create temporary table scramble (SELECT 
	employee_id.id,
    first_name.first_name,
    last_name.last_name
FROM
(
    -- randomise employee id
    SELECT eid.*,
        @row_num1:=@row_num1 + 1 'row_num'
    FROM
        (SELECT 
			emp1.id
		FROM
			employee emp1
		ORDER BY RAND()) eid, (SELECT @row_num1:=0) r) employee_id
JOIN
    (
    -- randomise first name
    SELECT fn.*,
        @row_num2:=@row_num2 + 1 'row_num'
    FROM
        (SELECT 
			emp1.first_name, emp1.employee_number
		FROM
			employee emp1
		ORDER BY RAND()) fn, (SELECT @row_num2:=0) r) first_name ON employee_id.row_num = first_name.row_num
JOIN
    (
    -- randomise last name
    SELECT ln.*,
        @row_num3:=@row_num3 + 1 'row_num'
    FROM
        (SELECT 
			emp2.last_name, emp2.employee_number
		FROM
			employee emp2
		ORDER BY RAND()) ln, (SELECT @row_num3:=0) r) last_name ON first_name.row_num = last_name.row_num);

UPDATE employee e
    JOIN scramble scramble ON e.id = scramble.id 
SET 
    e.first_name = scramble.first_name,
    e.last_name = scramble.last_name;