create table if not exists t1 (idcol1 int,t1col1 int, t1col2 int,t1col3 int );

create table if not exists t2 (idcol1 int,t2col1 int, t2col2 int, t2col3 int);

create or replace view t2_view (col1,col2,col3) as

select t1col1,t1col2,t1col3 from t1

union all

select t2col1,t2col2,t2col3 from t2

order by col1,col2;

Code: 1054 SQL State: 42S22 --- Unknown column 'col1' in 'order clause'

create or replace view t4_view (idcol1,col2,col3,col4) as

select t1.idcol1,t1col2,t1col3,t2.idcol1 from t1 join t2 on (t1.idcol1 = t2.idcol1)

union all

select t2.idcol1,t2col2,t2col3,t1.idcol1 from t2 join t1 on (t2.idcol1 = t1.idcol1)

order by idcol1,col2;

Code: 1052 SQL State: 23000 --- Column 'idcol1' in order clause is ambiguous