How can one query data of a specific length with Oracle…

You can use the SUBSTR function in Oracle to query data of a specified length.

The grammar is as follows:
The syntax is outlined as follows:

SUBSTR(string, start_position, length)

Parameter description:

1. String: the string that needs to be truncated.
2. The starting position for extraction, counted from 1.
3. length: the desired length to be cut.

Assume there is a table named employees with a field named name, and if you want to query the first 5 characters in the name field, you can use the following SQL statement:

SELECT SUBSTR(name, 1, 5) FROM employees;

This way, you can retrieve the first 5 characters of the name field.