Comma-Separated vs. JOIN ON Syntax in MySQL: What's the Real Difference?

Comma Separated Joins vs. JOIN ON Syntax in MySQL

MySQL offers multiple ways to perform joins, including the traditional comma-separated syntax and the newer JOIN ON approach.

Comma-Separated Joins

The comma-separated join syntax appends multiple tables in a comma-separated list after the FROM keyword. For example:

SELECT *
FROM Person, Worker
WHERE Person.id = Worker.id;

JOIN ON Syntax

The JOIN ON syntax explicitly defines join criteria using the ON clause. This syntax is often more readable and can make complex joins easier to understand.

SELECT *
FROM Person
JOIN Worker
ON Person.id = Worker.id;

Difference

Contrary to the question's premise, there is no difference between these two syntaxes. They both produce the same results.

Recommendation

The JOIN ON syntax is generally preferred from a readability and maintenance perspective. However, either syntax remains valid and functional in MySQL. The choice depends on which approach best fits the specific query and coding style.

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