ORACLE-Find Non-Numeric Rows in a Table

Sometimes you want to alter your table. For example you want to change the data type from varchar to numeric. But many times some rows prevents you to doing this.

Find the non-numeric rows;

select nvl(length(translate(trim(column_name),' +-.0123456789',' ')),0) from table_name

where nvl(length(translate(trim(column_name),' +-.0123456789',' ')),0) > 0

tip: by equal the where clause to 0 (zero) you can find the numeric columns.