MySQL選擇查詢在5.0和5.5之間的區別

Question

在MySQL 5.0.95和5.5.30上使用以下查詢。

在5.5.30上，它返回正確的結果（1個結果）。

在5.0.95上，它返回正確的結果，但有重復。 因此它返回了兩次（2個結果）。

我沒有在文檔中看到任何會導致這種情況的信息。

SELECT
  job.job_id, job.job_number, job.status, job_applicants.job_id, 
  job_applicants.user_id, job_applicants.accepted, 
  job_declined.job_id, job_declined.user_id, job_declined.declined
FROM job
    JOIN job_applicants ON job.job_id = job_applicants.job_id
    LEFT OUTER JOIN job_declined ON job.job_id = job_declined.job_id
WHERE 
    job_applicants.user_id = 6 AND job_applicants.accepted = 0 
    AND job.job_id NOT IN 
      (SELECT DISTINCT job_id FROM job_declined WHERE user_id = 6 and declined = 1)

Answer 1

這是job_declined的LEFT OUTER JOIN。 那不需要在第一個查詢中加入，只需要在子查詢中加入。 顯然是5.0.95。

SELECT
  job.job_id, job.job_number, job.status, job_applicants.job_id, 
  job_applicants.user_id, job_applicants.accepted
FROM job
    JOIN job_applicants ON job.job_id = job_applicants.job_id
WHERE 
    job_applicants.user_id = 6 AND job_applicants.accepted = 0 
    AND job.job_id NOT IN 
      (SELECT DISTINCT job_id FROM job_declined WHERE user_id = 6 and declined = 1)