if($XMFL = "信息","政企业务",if($XMFL = "工程","运营商业务",if($XMFL = "工程,信息","数智工程业务=运营商业务+政企业务","")))
正常,你的下拉框是不是分隔符是','
那就改成
if($XMFL = "信息","政企业务",if($XMFL = "工程","运营商业务",if($XMFL = "工程','信息","数智工程业务=运营商业务+政企业务","")))
返回值类型选字符串试试