JOIN vs. INNER JOIN: Are There Any Functional Differences?

JOIN and INNER JOIN: Interpret the differences

In SQL, JOIN is used to combine data from multiple tables based on a common key. There are several types of joins, including JOIN and INNER JOIN. Although both return similar results, the question arises: is there any difference between them?

Functional differences

Functionally speaking, JOIN and INNER JOIN are equivalent. They both return only rows that meet the join criteria. This means that the query results will be the same whether using JOIN or INNER JOIN.

Clarity and readability

However, readability is slightly different. INNER JOIN may be more explicit, especially in queries involving multiple join types. By using the word "INNER", it makes it clear that only matching rows should be returned, which helps improve clarity for complex queries.

Performance

Performance-wise, there is no significant difference between JOIN and INNER JOIN. Both types of joins use the same underlying algorithm to efficiently retrieve data. Therefore, the performance impact is negligible.

SQL implementation

The equivalence of JOIN and INNER JOIN is consistent across different SQL implementations. Major database vendors such as MySQL, PostgreSQL, and Oracle treat both connection types as functionally equivalent.

Conclusion

Ultimately, the choice between JOIN and INNER JOIN comes down to personal preference. Functionally, they are interchangeable. However, if readability is an issue, especially in queries with multiple join types, INNER JOIN may be a better choice for clarity. Otherwise, in most SQL implementations, either connection type can be used without affecting performance or functionality.

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