When insert new row, delete old data when data reaches 10 rows.

Hello

You can try below script code in Mysql database to delete records after insert 10 rows.

-- create
CREATE TABLE EMPLOYEE (
  empId INTEGER PRIMARY KEY,
  name TEXT NOT NULL,
  dept TEXT NOT NULL
);

-- trigger
CREATE TRIGGER InsTrigger AFTER INSERT
    ON EMPLOYEE FOR EACH ROW 
      IF (select count(*) FROM EMPLOYEE) > 2 THEN
        DELETE FROM EMPLOYEE;
      END IF;

-- insert
INSERT INTO EMPLOYEE VALUES (0001, 'Clark', 'Sales');
INSERT INTO EMPLOYEE VALUES (0002, 'Dave', 'Accounting');
INSERT INTO EMPLOYEE VALUES (0003, 'Ava', 'Sales');

yes you can use trigger to do this,

do something like following

create trigger delete_old_rows
after insert on your_table for each row begin
DECLARE totalrows INT;
  set totalrows  = ( select count(*) from your_table);
  if totalrows = 10
    then
      Delete FROM your_table LIMIT 3;  --here you define how many rows you have to delete
  end if;
end

use triggers