%if %sysfunc(attrn(&dsid,WHSTMT)) or %sysfunc(attrc(&dsid,MTYPE)) EQ VIEW %then %let nobs=%sysfunc(attrn(&dsid,NLOBSF)); %else %let nobs=%sysfunc(attrn(&dsid,NOBS));请教一下大神,%sysfunc(attrn(&dsid,WHSTMT)) or %sysfunc(attrc(&dsid,MTYPE)) EQ VIEW 这一段什么意思????