"Henry B. Hotz" <[EMAIL PROTECTED]> writes:You can imply the issue without obfuscating things. How about:
A CROSS JOIN or INNER JOIN is a simple Cartesian product, the same as you get from listing the two items at the top level of FROM. CROSS JOIN yields the same results as INNER JOIN ON (TRUE), that is, no rows are removed by qualification.
Okay, but that doesn't do the trick --- it implies that CROSS JOIN isn't equivalent to INNER JOIN ON (TRUE), when in fact they are equivalent, both as to result and performance characteristics. The issue at hand is that an explicit "a JOIN b" may not be equivalent to "FROM a, b".
I reworded the passage as
CROSS JOIN and INNER JOIN produce a simple Cartesian product, the same result as you get from listing the two items at the top level of FROM, but restricted by the join condition (if any). CROSS JOIN is equivalent to INNER JOIN ON (TRUE), that is, no rows are removed by qualification.
does that help?
'sarright. I was just wordsmithing without worrying about the meaning. -- The opinions expressed in this message are mine, not those of Caltech, JPL, NASA, or the US Government. [EMAIL PROTECTED], or [EMAIL PROTECTED]
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