INNER JOIN vs. WHERE Clause: Which is Better for Joining Tables in MySQL?

MySQL table connection: INNER JOIN and WHERE clause

MySQL provides two commonly used table connection methods: WHERE clause and INNER JOIN clause. Both achieve the same connection effect, but differ in syntax and readability.

WHERE clause syntax writes the join condition along with other filter conditions in the WHERE clause. This syntax is more common in relational database models, where a join is defined as the Cartesian product of tables filtered by a specific condition.

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INNER JOIN clause is part of the ANSI standard SQL syntax. It uses the ON keyword to explicitly define join conditions, followed by equivalence conditions between foreign key and primary key columns. This syntax is generally considered more readable, especially in complex queries involving multiple joins.

In MySQL, the WHERE clause and the INNER JOIN clause are equivalent and produce the same results when they join tables. However, the INNER JOIN syntax is generally recommended as it is more concise, more readable, and can be easily replaced with OUTER JOIN if needed.

Additionally, MySQL supports the STRAIGHT_JOIN clause, which allows you to specify the order in which tables are scanned during a join operation. This functionality is not available in the WHERE clause syntax.

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