ORA-01722：执行查询时编号无效

Question

我正在寻求帮助以解决Oracle SQL查询问题。我试图找到两列之间的区别。这是查询格式

((TO_CHAR (TRUNC (SYSDATE) + 
           numtodsinterval(DECODE(
          LAG(e.actualdeparttime, 1, 0) OVER (Partition by es.evstrname ORDER BY e.actualdeparttime),1,0, 
          (LAG(e.actualdeparttime, 1, 0) OVER (Partition by es.evstrname ORDER BY e.actualdeparttime))),'second'),'hh24:mi')) 
        - (TO_CHAR (TRUNC (SYSDATE) + numtodsinterval(DECODE( e.actualarrivetime, -1, 0,  e.actualarrivetime),   'second'),'hh24:mi'))) as time_taken

查询显示和错误。请帮忙。谢谢

GG