Re: Index usage when bitwise operator is used
| От | Kevin Grittner |
|---|---|
| Тема | Re: Index usage when bitwise operator is used |
| Дата | |
| Msg-id | 46ED7CCD.EE98.0025.0@wicourts.gov обсуждение исходный текст |
| Ответ на | Index usage when bitwise operator is used ("W.Alphonse HAROUNY" <wharouny@gmail.com>) |
| Ответы |
Re: Index usage when bitwise operator is used
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| Список | pgsql-performance |
>>> On Thu, Sep 13, 2007 at 7:30 AM, in message <f97d4e240709130530ve3cc522g61ccca23335618f4@mail.gmail.com>, "W.Alphonse HAROUNY" <wharouny@gmail.com> wrote: > and each binary value of [variableCategory] may only hold a single binary > '1'. > TBL1.CATEGORY & TBL2.CATEGORY <> 0 //-- where & is the AND bitwise > operator What about saying?: TBL1.CATEGORY = TBL2.CATEGORY If your indexes include this and the other columns which cause the tables to be related, one or both of them stand a pretty good chance of evaluating to the lowest-cost method to join the tables. Forcing a query to use an index outside of it being the cheapest path is rarely productive. -Kevin
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