How to select all records if the WHERE condition is not received?

Question

SQL

For example, there is a request
SELECT * FROM tabletest WHERE id=1
id that comes as a parameter, how to leave the same request structure, but select all values. Is there a replacement * in the condition.
For example
SELECT * FROM tabletest WHERE id=*

Answer 1

build normally requests with the help of builders and not suffer.

Answer 2

Alternatively, you can use the OR condition. But in this case, you will have to pass the same id twice in the request. You will get something similar to this:
SELECT * FROM tabletest WHERE id=? OR '*'=?