Do not compare values against the NULL literal or an empty string

To test for nulls, use only the comparison conditions IS NULL and IS NOT NULL. Any other comparison with nulls will result in NULL.

Keep in mind that an empty string is equivalent to a NULL literal.

Noncompliant Code Example

if var = null then
  -- code
end if;

Or:

if other_var = '' then
  -- code
end if;

Compliant Solution

if var is null then
  -- code
end if;

if other_var is null then
  -- code
end if;