What is an Oracle ORA-01722 error?

Run the same statement selectcode_idcode on both databases, locate -- here the error with quotation marks is okorderbycode_id a normal, but the other reports an error ORA-01722, the same field type, the same database version, after

Run the select code_id code Statement on both databases, code_value name from code_value_t t where code_id like '0 _ 'and class_code = 22 -- if an error is added here, OK order by code_id is a normal one, but the other reports an error ORA-01722, the same field type, same database version, later

Execute the same statement on two databases.

Select code_id code, code_value name

From code_value_t t

Where code_id like '0 _'

And class_code = 22 <-- if an error occurs, enclose the quotation mark ("OK ").

Order by code_id

A normal, the other but reported an error ORA-01722, the same field type, the same database version, and then found in the where type conversion, if added with single quotes, do not report an error, find the data in the database that reported the error and find that one of the data items is of the string type. An error occurred while converting oracle to numeric comparison. Therefore, delete the test data OK.