Not sure what are your looking for but try below
Load *,if(isnum(Column1)=0 or isnum(Column2)=0,'String','Num') as Flag from tableName;
Load * from Temp
drop table Temp;
Logic is like
1: load all data from sheet flag on the basis of data in column
2: Filter out data from table created in 1 st step load only num data.
You can modify logic as per your requirement.