1

I'm learning mysql. Under all cases, is Join the same as Cross Join? For example, this query

SELECT * FROM table t1
JOIN table t2

Will always be the same as

SELECT * FROM table t1
CROSS JOIN table t2

Even if I add WHERE, GROUP BY, HAVING, LIMIT, ORDER etc.... conditions afterwards, JOIN and CROSS JOIN will always yield the same results?

Thanks

2

INNER, OUTER, and CROSS are ignored by MySQL. The ON and WHERE control which type of JOIN it is.

In your examples you have nothing tying the tables together, hence operates like a CROSS JOIN.

GROUP BY, etc have no impact.

  • 1
    That's not enirely correct (about the OUTER). The FROM a OUTER JOIN b will produce a syntax error. – ypercubeᵀᴹ May 13 '15 at 21:32
  • I stand corrected. – Rick James May 13 '15 at 23:07

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