NATURAL JOIN syntax is anti-pattern: The purpose of the query is less obvious; the columns used by the application is not clear the columns used can change “unexpectedly” The syntax goes against the modularity rule, about using strict typing whenever possible. Explicit is almost universally better. Because of this, I don’t recommend the syntax in … Read more
Venn diagrams are not very helpful for understanding natural join or inner join. Most Venn diagrams associated with joins on Stack Overflow are parroted worthless misrepresentations–even in cases where a Venn diagram could be useful. Here are some valid uses of Venn diagrams for SQL natural join: If you ignore column order, we can have … Read more
One significant difference between INNER JOIN and NATURAL JOIN is the number of columns returned. Consider: TableA TableB +————+———-+ +——————–+ |Column1 | Column2 | |Column1 | Column3 | +———————–+ +——————–+ | 1 | 2 | | 1 | 3 | +————+———-+ +———+———-+ The INNER JOIN of TableA and TableB on Column1 will return SELECT * … Read more