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@ -254,7 +254,7 @@ lower leftjoin has min LHS of {B} and min RHS of {C,D}. Given such |
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information, join_is_legal would think it's okay to associate the upper |
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information, join_is_legal would think it's okay to associate the upper |
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join into the lower join's RHS, transforming the query to |
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join into the lower join's RHS, transforming the query to |
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B leftjoin (A leftjoin (C innerjoin D) on Pa) on (Pbcd) |
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B leftjoin (A leftjoin (C innerjoin D) on Pa) on (Pbcd) |
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which yields totally wrong answers. We prevent that by forcing the min LHS |
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which yields totally wrong answers. We prevent that by forcing the min RHS |
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for the upper join to include B. This is perhaps overly restrictive, but |
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for the upper join to include B. This is perhaps overly restrictive, but |
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such cases don't arise often so it's not clear that it's worth developing a |
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such cases don't arise often so it's not clear that it's worth developing a |
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more complicated system. |
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more complicated system. |
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