问(SQL Vertica)创建一个新表，删除单个列中具有重复项的行

EN

CREATE TABLE test (
  id INT,
  exam_id INT
);
INSERT INTO test (id,exam_id) VALUES (1,1);
INSERT INTO test (id,exam_id) VALUES (2,1);
INSERT INTO test (id,exam_id) VALUES (3,2);
INSERT INTO test (id,exam_id) VALUES (4,2);

delete from test where id in (

select id from (SELECT 
   id, 
  exam_id,
   ROW_NUMBER() OVER (
      PARTITION BY exam_id
      ORDER BY exam_id
   ) row_num
FROM 
   test
ORDER BY 
   id) x where row_num =1) ;

  select * from test;