``` create table t(s); select * from t a join t b order by s; -- no error select * from t a join t b order by s,length(s); -- ambiguous column name: s ``` Why an error for the second case and not the first?
``` create table t(s); select * from t a join t b order by s; -- no error select * from t a join t b order by s,length(s); -- ambiguous column name: s ``` Why an error for the second case and not the first?