解决方案1：

WITH top_records AS (SELECT PARENT_CODE, PARENT_NAME, Course_Version, Course_Locale, Timestamp, RANK() OVER (PARTITION BY PARENT_CODE ORDER BY Course_Version DESC, Timestamp DESC) RN FROM Courselibrary WHERE Course_Locale = 'en_US') Select * from top_records where RN = 1;

解决方案2：

Select PARENT_CODE, PARENT_NAME, Course_Version, Course_Locale, Timestamp from (SELECT PARENT_CODE, PARENT_NAME, Course_Version, Course_Locale, Timestamp, RANK() OVER (PARTITION BY PARENT_CODE ORDER BY Course_Version DESC, Timestamp DESC) RN FROM Courselibrary WHERE Course_Locale = 'en_US') Where RN = 1;

在mysql 8+中，您将使用 row_number() . 在早期版本中，可以使用相关子查询，但这假定每行上都有一个唯一的标识符。因此，将表定义为：

create table CourseLibrary (
    CourseLibrary_Id int auto_increment primary key,
    Parent_code varchar(250),
    Parent_Name varchar(250),
    Course_Version varchar(250),
    Course_Locale varchar(250),
    Timestamp varchar(250)
);

我还认为 timestamp 应存储为日期/时间值，而不是字符串。
然后你可以做：

select cl.*
from CourseLibrary cl
where cl.CourseLibrary_Id = (select cl2.CourseLibrary_Id
                             from CourseLibrary cl2
                             where cl2.Parent_code = cl.Parent_code
                             order by Course_Version desc,
                                      (course_locale = 'en_US') desc,
                                      timestamp desc
                             limit 1
                            );

你真的不需要 CourseLibrary_Id . 任何主键都可以。但是，您的表没有id，所以最好使用自动递增的id。

select max(timestamp) as timestamp, parent_code, parent_name, course_version, course_locale from (select * from courselibrary where parent_code='UXPUEMBR007' and (select count(*) from courselibrary where parent_code='UXPUEMBR007') >= 1 and course_version=(select max(course_version) from courselibrary where parent_code='UXPUEMBR007') and course_locale='en_US') as resultset group by parent_code, parent_name, course_version, course_locale;