F_TABLE_NUMBER_RANGE equivalent in Postgresql
От | Yuan HOng |
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Тема | F_TABLE_NUMBER_RANGE equivalent in Postgresql |
Дата | |
Msg-id | CANvi9-2uJUWGc8_VJMPq1NGnxVt=KjQihKvorjyLc3WL2MG4DA@mail.gmail.com обсуждение исходный текст |
Ответы |
Re: F_TABLE_NUMBER_RANGE equivalent in Postgresql
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Список | pgsql-sql |
Hi, With MS-SQL sever, there is a built-in utility function dbo.F_TABLE_NUMBER_RANGE which generates a list of number between the given range. For example: select dbo.F_TABLE_NUMBER_RANGE(1, 5) will return: number ----------- 1 2 3 4 5 This is extremely convenient for generating consecutive dates. For example, I want to find out the daily sales information and if on some day there is no sales, the query should return 0 instead of a missing date. In this case it is necessary to first create a list of consecutive dates and then left join to some fact table. With the range function I can simply write something like select start_date + interval number from dbo.F_TABLE_NUMBER_RANGE(1, number_of_days) How does one accomplish such task with Postgresql? -- Hong Yuan 大管家网上建材超市 装修装潢建材一站式购物 http://www.homemaster.cn
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