Re: Re: Data type confusion
От | Josh Berkus |
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Тема | Re: Re: Data type confusion |
Дата | |
Msg-id | web-97584@davinci.ethosmedia.com обсуждение исходный текст |
Ответ на | Re: Data type confusion (Allan Engelhardt <allane@cybaea.com>) |
Ответы |
Re: Re: Data type confusion
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Список | pgsql-sql |
Allan, > I see now what you are trying to do. It sort of makes sense, but I'm > still really reluctant to give (semantic or otherwise) meaning to > "yesterday divided by tomorrow" ..... I don't agree. Consider, for example, this statement: '30 weeks ago'::INTERVAL / '2 weeks'::INTERVAL = -15 Just as -30 / 2 = -15 To phrase the equation above: "How many two week periods is thirty weeks ago? Minus fifteen, or fifteen ago." This makes perfect sense to me. > It seems to me that such a function would be more generally useful > than the division of intervals. What you really want to do is not to > divide intervals, but to express them in different time units. Or am > I missing something (again)? From my pespective? Yes, you are. (For one thing, the CONVERT function in Postgres converts between unicode character sets, not data-types). Look, if I'm designing a payroll application for a company with bi-weekly payroll, I will want a report that shows how many payroll periods for which an employee has been employed. Thus I will want to: periods_employed := (current_timestamp - date_hired) / '2 weeks'::INTERVAL I don't want to go through a bunch of non-ANSI SQL-compliant conversion functions to do it. Especially not as this is just what the ANSI SQL data type and operator specs are designed to support. -Josh ______AGLIO DATABASE SOLUTIONS___________________________ Josh Berkus Complete informationtechnology josh@agliodbs.com and data management solutions (415) 565-7293 for law firms, small businesses fax 621-2533 and non-profit organizations. San Francisco
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