Theta join

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The theta join is probably the least used SQL join type. Here's an example of a theta join in use. Lets say you have a table of daily sales, and want a report showing the sales to date for each day.

CREATE TABLE test (d datetime, v INT)
 
INSERT INTO test VALUES ('20100101', 0)
INSERT INTO test VALUES ('20100102', 20)
INSERT INTO test VALUES ('20100103', 30)
 
SELECT b.d, SUM(a.v) FROM test a JOIN test b ON a.d <= b.d
GROUP BY b.d

The result looks like this:

Invalid language.

You need to specify a language like this: <source lang="html4strict">...</source>

Supported languages for syntax highlighting:

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1/01/2010 12:00:00.000 AM	0
2/01/2010 12:00:00.000 AM	20
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