Find column semantics

When migrating from single-byte code to multi-byte code character sets, one way to move your data without data loss is to change the semantics used. In other words, VARCHAR2 and CHAR type columns can be redefined to use character semantics instead of the default byte semantics.

A schema-by-schema overview of the tables and column involved can be extracted by using the query below:

select owner "owner",
                CASE 
                    WHEN char_used = 'B' then 'BYTE'
                    WHEN char_used = 'C' then 'CHAR'
                END "semantics"
,count(*) "antall"
from dba_tab_columns
where owner in ('SCOTT','RYAN')
and data_Type in ('CHAR','VARCHAR2')
group by OWNER, ROLLUP(char_used);

owner	semantics	antall
SCOTT	BYTE	62
SCOTT	CHAR	610
SCOTT		672
RYAN	BYTE	486
RYAN		486

In this example, the SCOTT schema contains columns of both semantics types.
The schema RYAN contains only the default, BYTE.