Final answer:
Forgetting to use a JOIN statement generally leads to a Cartesian product and incorrect results. The results depend on the type of SQL used and the query structure. Different JOIN types are used to group data based on the relationships and data requirements.
Step-by-step explanation:
If you forget to use a JOIN statement when selecting data from multiple tables, typically it depends on the type of SQL you are using and how you've structured your query. If you are selecting from multiple tables without specifying the type of join, most SQL databases will execute a Cartesian product or cross join. This could result in a very large result set that pairs each row from the first table with each row from the second table, leading to incorrect results unless that was the intended operation.
No table is inherently more correct than the other; it just depends on the data you need and the context of your query. To group the data differently, you might consider using different types of JOIN operations like INNER JOIN, LEFT JOIN, RIGHT JOIN, or FULL JOIN depending on the relationship between the tables and the data you require. The advantages depend largely on the specific data and the requirements of the query.
Switching between tables while answering questions about JOINs or queries is often done to provide context and examples of different ways data can be combined or to illustrate the effects of different types of joins.