SQL — true or false?

Exercise and reference answers

Questions

1. Statement is true

   Yes

   Statement

   JOIN without specifying a condition produces a Cartesian product.

2. Statement is true

   No

   Statement

   GROUP BY must accompany every SELECT that uses an aggregate.

3. Statement is true

   Yes

   Statement

   HAVING filters groups; WHERE filters rows.

4. Statement is true

   No

   Statement

   NULL = NULL evaluates to TRUE in standard SQL.