sql("SampleDashboard","select count(distinct office_name,model_name,category_name) totalCount from ProStateDetail where ${if(len(ts_xh)=0,'1=1','model_name like "%'+ts_xh+'%" ')} and category_name in ('"+ts_pl+"') and category_model_state='"+is_ts+"' ",1,1)这里面的if该怎么使用?