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2 Replies Latest reply: Apr 2, 2011 3:05 AM by 811822 RSS

MINUS Set Operator

811822 Newbie
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Hi,

I was browsing through the examples of the manual and found this particular one peculiar:
Example 19–16 Set Operators: MINUS Query
<query id="q1BBAQuery"><![CDATA[
R1 MINUS R2
]]></query>
Example 19–17 Set Operators: MINUS Relation Input R1
Timestamp Tuple Kind Tuple
1500: + 10,40
2000: + 10,30
2000: - 10,40
3000: - 10,30
Example 19–18 Set Operators: MINUS Relation Input R2
Timestamp Tuple Kind Tuple
1000: + 11,20
2000: + 10,40
3000: - 10,30
Example 19–19 Set Operators: MINUS Relation Output
Timestamp Tuple Kind Tuple
1000: + 10,40.0
2000: - 10,40.0
Why is the tuple 10,40 inserted at 1000? Is MINUS the difference when R2(t) is subtracted from R1(t)?

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