时间类型计算- FineReport帮助文档 - 全面的报表使用教程和学习资料 (fanruan.com)
MINUTE(B2) - MINUTE(A2)
试试帆软的单元格公式
DATESUBDATE("2008-08-08","2008-06-06","m")
DATESUBDATE(CONCATENATE(format(today(),"yyyy-MM-dd")," ",b7),CONCATENATE(format(today(),"yyyy-MM-dd")," ",a7),"m")