CROSS JOIN - new joint type

stereo_web · **Joined:** 11-02-2010 10:02 PM **Posts:** 3

Hi Guys,

I was using VS 2008 to build reports. Using GUI, I added table, selected fields created filters, etc ... and for the first time in my life I saw type of a joint called 'CROSS JOIN'

I was trying to read this article http://en.wikipedia.org/wiki/Join_(SQL)#Cross_join on WIKI, but still I don't really see a difference.

What am I missing here? What sort of a joint has Microsoft invented now?

Cheers,
Stereo_Web

maxseo · **Joined:** 06-02-2010 10:02 PM **Posts:** 153

Quote:

A cross join that does not have a WHERE clause produces the Cartesian product of the tables involved in the join. The size of a Cartesian product result set is the number of rows in the first table multiplied by the number of rows in the second table. The following example shows a Transact-SQL cross join.

The above quote is from MSDN support.

What it means is that if in table A you had 10 records and table B had 100 records, and 8 records from table A would match the table B foreign keys, that means you would get 800 records from running that SQL query with that CROSS JOIN

CROSS JOIN - new joint type

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