  DELETE FROM emp a
    WHERE rowid > (
      SELECT min(rowid)
      FROM   emp b
      WHERE  a.emp_id = b.emp_id
    );

  CREATE TABLE emp2 AS
    SELECT distinct *
    FROM   emp;

  DROP TABLE emp;

  RENAME emp2 TO emp;

  DELETE FROM emp
    WHERE rowid NOT IN (
      SELECT    MIN(rowid)
      FROM      emp
      GROUP BY  emp_id
    );

  DELETE FROM emp a
    WHERE EXISTS (
      SELECT 'true'
      FROM   emp b
      WHERE  b.emp_id = a.emp_id
        AND  b.rowid < a.rowid
    );

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