PL/SQL

Using the same value on either side of a binary operator is almost always a mistake. In the case of logical operators, it is either a copy/paste error and therefore a bug, or it is simply wasted code, and should be simplified.

This rule ignores operators +, * and ||, and expressions: 1=1, 1<>1, 1!=1, 1~=1 and 1^=1.

Noncompliant Code Example

SELECT code
  FROM Person
  WHERE first_name IS NULL OR first_name IS NULL; -- Noncompliant

SELECT * FROM Users
  INNER JOIN Clients ON Clients.id = Clients.id; -- Noncompliant

Compliant Solution

SELECT code
  FROM Person
  WHERE first_name IS NULL OR last_name IS NULL;

SELECT * FROM Users
  INNER JOIN Clients ON Clients.id = Users.id;