--将两个表上下连接 --日期一样的问题,将两个表新加标记1,2,先以时间排序,再以标记排序 WITH t AS ( SELECT EMPLOYEE_ID, POSITION, LAST_UPDATE_DT, 1 AS source FROM EMPLOYEE_INFO UNION ALL SELECT EMPLOYEE_ID, NEW_POSITION AS POSITION, UPDATE_DT AS LAST_UPDATE_DT, 2 AS source FROM EMPLOYEE_UPDATE ), ranked AS ( SELECT EMPLOYEE_ID, POSITION, L...