Final answer:
In the context of SQL and databases, the statement is true as n tables would require n-1 join operations to merge them based on a related column.
Step-by-step explanation:
The statement that the number of join operations needed is the number of tables involved minus one can be considered true in the context of SQL database operations. When you want to combine rows from two or more tables based on a related column between them, you perform a join operation. If you have two tables, you need one join to connect them. If you have three tables, you would need two joins, and so on. Therefore, if you have 'n' tables, you would need 'n-1' joins. Considering this, if we're dealing with database table joins, the statement stands true.
Four types of joins: left, right, inner, and outer. In general, you'll only really need to use inner joins and left outer joins. Which join type you use depends on whether you want to include unmatched rows in your results: If you need unmatched rows in the primary table, use a left outer join.