Baffled by "Group By" - Please help!
От | Matt Friedman |
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Тема | Baffled by "Group By" - Please help! |
Дата | |
Msg-id | 002b01c0b4a5$b7d188e0$03284d18@mattq3h8budilr обсуждение исходный текст |
Ответы |
Re: Baffled by "Group By" - Please help!
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Список | pgsql-general |
For some reason, probably because I'm not understanding very well, I'm getting some duplicated rows for this query (below). My understanding is that "group by" brings all the rows together where the indicated columns are equal and then applies the aggregate to the column indicated; in this case: "sum". What am I missing? I'm not seeing why this query doesn't group everything and then return unique rows. Please let me know if you need more info and I will send it. SELECT index_uri.uri, index_uri.description, index_uri.title, index_type.type, index_type.icon, SUM(index.word_count) FROM index, index_word, index_uri, index_type WHERE ( index_word.word ~'eat.*' -- could be more or fewer comparisons here. OR index_word.word ~'disord.*' ) AND index_word.word_id=index.word_id AND index_uri.uri_id = index.uri_id AND index_type.type_id = index_uri.type_id GROUP BY index_uri.uri, index_uri.description, index_uri.title, index_type.type, index.word_count, index_type.icon ORDER BY sum DESC Matt Friedman
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