Question

我希望通过一封distinct电子邮件获取一些数据。

我的代码如下：

SELECT DISTINCT Email, 
                Degree, 
                Majority
FROM   job_education a 
WHERE  a.Status = 'Active' 
AND a.IdEducationLevel = (
                          SELECT Max(b.IdEducationLevel) 
                          FROM job_education b 
                          WHERE b.Status='Active' 
                          AND  a.Email = b.Email
                         )

感谢您的善意

Answer 1

你应该使用连接
（子选择不能看到表a的上部引用）

SELECT DISTINCT Email, 
            Degree, 
            Majority 
     FROM   job_education a 
     INNER JOIN (
        SELECT  b.Email,  Max(b.IdEducationLevel)  max_IdEducationLevel
        FROM job_education b 
        WHERE b.Status='Active' 
        GROUP BY b.Email

     ) t  ON    a.Email = t.Email and a.IdEducationLevel = t.maxy_IdEducationLevel
     WHERE  a.Status = 'Active'

Answer 2

你的代码应该没问题，虽然我会修复表别名：

SELECT je.*
FROM job_education je
WHERE je.Status = 'Active' AND
      je.IdEducationLevel = (SELECT MAX(je2.IdEducationLevel)
                             FROM job_education je2
                             WHERE je2.Status = 'Active' AND je2.Email = je.Email
                            );

如果您为给定的电子邮件获取多行 - 并且您只想要一行 - 那么在子查询中使用更好的ID：

SELECT je.*
FROM job_education je
WHERE je.Status = 'Active' AND
      je.job_education_id = (SELECT je2.job_education_id
                             FROM job_education je2
                             WHERE je2.Status = 'Active' AND je2.Email = je.Email
                             ORDER BY IdEducationLevel DESC, job_education_id DESC
                             LIMIT 1
                            );

为此，我发明了一个名为job_education_id的id。请注意，此查询使用ORDER BY和LIMIT而不是聚合函数。

如何获取最大ID的MAX数据

2 个答案: