根据SSAS表格中的当前年度，月份和日期过滤来计算上个月

Question

我在SSAS表格模型中具有这样的当前代码

KPI RiskClass MTD:=CALCULATE ([KPI RiskClass WF];
                  FILTER (
                      ALL ('Contract Activation Date');
                     'Contract Activation Date'[Month] = MAX ('Contract Activation Date'[Month])
                      && 'Contract Activation Date'[Year] = MAX ('Contract Activation Date'[Year])
                          && 'Contract Activation Date'[Date] <= MAX ('Contract Activation Date'[Date] )
                  ))

所以我想根据上述过滤条件计算上个月的数据