select *from cor_cp_cd xwhere 1=1 写法一:and x.model_code in ('"+replace(sql("server","select model_code from cor_cp_cd",1),",","','")+"') 写法二:${if(fr_username = '003900'," ","and x.model_code in ('"+replace(sql("server","select model_code from cor_cp_cd",1),",","','")+"')")}为什么写法一是错的?求解释