通信通道的文件结束

Question

SELECT (SELECT MAX(BEGINDATE.BEGIN_DATE)
              FROM (SELECT P.ARCHIVES_BUILD_DATE AS BEGIN_DATE 
                      FROM PEOPLE_ARCHIVES
                     WHERE PEOPLE_ARCHIVES.PEOPLE_SN = P.PEOPLE_SN
                    UNION 
                    SELECT P.DJ_DATE 
                      FROM PEOPLE_ARCHIVES
                     WHERE PEOPLE_ARCHIVES.PEOPLE_SN = P.PEOPLE_SN
                    UNION 
                    SELECT JKWT.NCZ_YES_DATE
                      FROM PEOPLE_JKWT
                     WHERE PEOPLE_JKWT.PEOPLE_SN = P.PEOPLE_SN) BEGINDATE) AS YES_BEGIN_DATE
      FROM PEOPLE_ARCHIVES P
     INNER JOIN PEOPLE_JKWT JKWT ON P.PEOPLE_SN = JKWT.PEOPLE_SN补充：应该是union的问题，求解？

Answer 1

通信通道的文件结束 表示你与服务器断开了，和sql没关系，看看网络是否正常吧。

Answer 2

SELECT (SELECT MAX(BEGINDATE.BEGIN_DATE)
              FROM (SELECT P.ARCHIVES_BUILD_DATE AS BEGIN_DATE 
                      FROM dual
                    UNION 
                    SELECT P.DJ_DATE 
                      FROM dual
                    UNION 
                    SELECT JKWT.NCZ_YES_DATE
                      FROM dual) BEGINDATE) AS YES_BEGIN_DATE
      FROM PEOPLE_ARCHIVES P
     INNER JOIN PEOPLE_JKWT JKWT ON P.PEOPLE_SN = JKWT.PEOPLE_SN
但是我这样写就不报错了，但是没有数据。