generate-series

问题 I have unevenly distributed data(wrt date) for a few years (2003-2008). I want to query data for a given set of start and end date, grouping the data by any of the supported intervals (day, week, month, quarter, year) in PostgreSQL 8.3 (http://www.postgresql.org/docs/8.3/static/functions-datetime.html#FUNCTIONS-DATETIME-TRUNC). The problem is that some of the queries give results continuous over the required period, as this one: select to_char(date_trunc('month',date), 'YYYY-MM-DD'),count

问题 When I run the SQL Query: select generate_series(0,g) from ( select date(date1) - date(date2) as g from mytable ; It returns an error: INFO: Function "generate_series(integer,integer)" not supported. ERROR: Specified types or functions (one per INFO message) not supported on Redshift tables. But when I run this query: select generate_series(0, g) from (select 5 as g) It returns the below response: generate_series ----------------- 0 1 2 3 4 5 (6 rows) Why does the second query work, while the

问题 Let's say I have a this search query like this: SELECT COUNT(id), date(created_at) FROM entries WHERE date(created_at) >= date(current_date - interval '1 week') GROUP BY date(created_at) As you know then for example I get a result back like this: count | date 2 | 15.01.2014 1 | 13.01.2014 9 | 09.01.2014 But I do not get the days of the week where no entries where created. How can I get a search result that looks like this, including the days where no entries where created? count | date 2 | 15

问题 In classification_indicator_id column I have some digits. I would like to sum this digits in 1 day series. I wrote below query select a.data_start::date, a.segment1::integer as "Segment1" from ( select data as data_start, (select sum(classification_indicator_id) from classifications where classification_indicator_id = 3)::integer as segment1 from generate_series('2013-03-25'::timestamp without time zone, '2013-04-01'::timestamp without time zone, '1 day'::interval) data ) a group by a.data

问题 This is a follow on question from @Erwin's answer to Efficient time series querying in Postgres. In order to keep things simple I'll use the same table structure as that question id | widget_id | for_date | score | The original question was to get score for each of the widgets for every date in a range. If there was no entry for a widget on a date then show the score from the previous entry for that widget. The solution using a cross join and a window function worked well if all the data was

问题 In PostgreSQL, is it possible to generate a series of repeating numbers? For example, I want to generate the numbers 1 to 10, with each number repeated 3 times: 1 1 1 2 2 2 3 3 3 .. and so on. 回答1: You could cross join it to a series of 3: SELECT a.n from generate_series(1, 100) as a(n), generate_series(1, 3) 回答2: You could try integer division like this: SELECT generate_series(3, 100) / 3 回答3: For such small numbers CROSS JOIN two VALUES expressions: SELECT n FROM (VALUES (1),(2),(3)) x(r) -

问题 I'm trying to obtain a list of dates within range, similar to the command NOW() in PostgreSQL, with the only difference that now() , returns only the current date. If I execute it as follows I obtain: select now(); 2013-09-27 15:27:50.303-05 Or by example, I could do this: select now() - interval '1' day; and the result is yesterday 2013-09-27 15:27:50.303-05 What I need is a query that could return a list with every date within a given range, so if I provide 2013-09-20 and 2013-09-27 (I'm

问题 I'm trying to create a function that compares if the beginning of an input string matches one of the possibilities generated from the combinations in multiple System.Arrays . The result of this function will be a returned object with the input GroupName we received and if it's a valid name or not $true/$false . Array1: Country ------- BEL NLD Array2: Color ---- Green Red Array3: Type Object ---- ------ Fruit Banana Veggetables Aubergine Fruit Appel Veggetables Carrot Fruit Peer Generated list

问题 I have some ids in a table, but there are gaps in between. I want to select these gaps. For example, the integer numbers in my table are: 1 2 5 9 15 And I want to select: 3 4 6 7 8 10 11 12 13 14 My version of PostgreSQL is 9.1.1, so I cannot use int4range. 回答1: Use generate_series() and LEFT JOIN to the table: SELECT g.nr FROM generate_series(1,15) g(nr) LEFT JOIN tbl USING (nr) WHERE tbl.nr IS NULL; Replace all occurrences of nr with your actual column name. Or use one of the other basic

问题 Postgres version 9.4.18, PostGIS Version 2.2. Here are the tables I'm working with (and can unlikely make significant changes to the table structure): Table ltg_data (spans 1988 to 2018): Column | Type | Modifiers ----------+--------------------------+----------- intensity | integer | not null time | timestamp with time zone | not null lon | numeric(9,6) | not null lat | numeric(8,6) | not null ltg_geom | geometry(Point,4269) | Indexes: "ltg_data2_ltg_geom_idx" gist (ltg_geom) "ltg_data2_time