Query by the value of a non-existent column using a standard ANSI join, and you'll get an error. Do the same thing in a sub-query, and you'll silently get the wrong result because the condition will effectively be ignored.
== Noncompliant Code Example
[source,text]
----
CREATE TABLE rule (
id integer(10),
.... );
CREATE TABLE issue (
rule_id integer(10),
... );
SELECT id, status
FROM issue
WHERE rule_id in (
SELECT rule_id -- Noncompliant. Condition ignored and all issues selected
FROM rule
WHERE ...
)
