postgresql-9.4

问题 I have the following problem: I created two points, for example: SRID=3857;POINT Z (62780.8532226825 5415035.177460473 100) SRID=3857;POINT Z (62785.8532226825 5415035.177460473 70) As you can see, there is 5m difference in X coordinates, and 30m in Z coordinates. When I run a.distance(b) in django shell, it returns 5 , which is wrong. However, whenIi run in a psql shell: SELECT ST_3DDistance(a.coordinates, b.coordinates) FROM restapi_entityxyz a, restapi_entityxyz b WHERE a.external_id=

问题 I have this query SELECT DISTINCT u.email, ( SELECT count(DISTINCT o.id) FROM orders o INNER JOIN cart_dates cd ON cd.order_id = o.id WHERE u.id = o.user_id ) as count FROM users u How can I get rows only when count is, for example, < 20? 回答1: you can use group by and having clause. select u.email from users u inner join orders o on o.user_Id = u.id inner join card_dates cd on cd.order_id = o.id group by u.email having count(distinct o.id) < 20 来源： https://stackoverflow.com/questions/59709945

问题 I have this query SELECT DISTINCT u.email, ( SELECT count(DISTINCT o.id) FROM orders o INNER JOIN cart_dates cd ON cd.order_id = o.id WHERE u.id = o.user_id ) as count FROM users u How can I get rows only when count is, for example, < 20? 回答1: you can use group by and having clause. select u.email from users u inner join orders o on o.user_Id = u.id inner join card_dates cd on cd.order_id = o.id group by u.email having count(distinct o.id) < 20 来源： https://stackoverflow.com/questions/59709945

问题 I have this query SELECT DISTINCT u.email, ( SELECT count(DISTINCT o.id) FROM orders o INNER JOIN cart_dates cd ON cd.order_id = o.id WHERE u.id = o.user_id ) as count FROM users u How can I get rows only when count is, for example, < 20? 回答1: you can use group by and having clause. select u.email from users u inner join orders o on o.user_Id = u.id inner join card_dates cd on cd.order_id = o.id group by u.email having count(distinct o.id) < 20 来源： https://stackoverflow.com/questions/59709945

问题 I have a Postgres 9.4 database with a table like this: | id | other_id | current | dn_ids | rank | |----|----------|---------|---------------------------------------|------| | 1 | 5 | F | {123,234,345,456,111,222,333,444,555} | 1 | | 2 | 7 | F | {123,100,200,900,800,700,600,400,323} | 2 | (update) I already have a couple indexes defined. Here is the CREATE TABLE syntax: CREATE TABLE mytable ( id integer NOT NULL, other_id integer, rank integer, current boolean DEFAULT false, dn_ids integer[]

问题 I have a Postgres 9.4 database with a table like this: | id | other_id | current | dn_ids | rank | |----|----------|---------|---------------------------------------|------| | 1 | 5 | F | {123,234,345,456,111,222,333,444,555} | 1 | | 2 | 7 | F | {123,100,200,900,800,700,600,400,323} | 2 | (update) I already have a couple indexes defined. Here is the CREATE TABLE syntax: CREATE TABLE mytable ( id integer NOT NULL, other_id integer, rank integer, current boolean DEFAULT false, dn_ids integer[]

问题 I want to get all records where any value in jsonb field contains a text regardless of key. For example: field contains json {k1: 'hello', k2: 'world'} . I want to get this record by the text 'hello'. I don't care about keys or any json structure, only values. One dirty hack is to cast the field to varchar where jsonb_field::varchar like ... , but this is ugly and it will match keys and {} as well. Another dirty hack looks like this: SELECT * FROM mytable AS m1 WHERE ( SELECT string_agg(value

问题 MyTable.MyField in my PostgreSQL database contains the following (simplified) JSON block: { "base": { "fields": [ { "fieldid": "c12f", "fieldname": "sizes", "choices": [ { "choiceid": "2db3", "size": "small" }, { "choiceid": "241f", "size": "medium" }, { "choiceid": "3f52", "size": "large" } ], "answer": "241f" } ] } } How can I use the value of answer to extract the chosen size from the choices array please (i.e. in this case "medium")? (Note: I have tried. For a TLDR version of this

问题 Environment: PostgreSQL EDB 9.4.1 OS:rhel 7 I have configured streaming replication with continuous archiving. I have performed the steps below for switch-over and switchback. I have read this other articles. I am confused what happens if the archive location is not a shared location. I have followed the steps below for switchover and switchback. SWITCHOVER At the master (192.xxxx.128) pg_ctl -D /opt/PostgresPlus/9.4AS/data stop --mode=fast Create recovery.conf : standby_mode = 'on' primary

问题 I'm building an API using the Go (1.6.x) sql package along with with PostGres (9.4). Should my prepared statements have application or request scope? Having read the docs it would seem more efficient to scope them at the application level to reduce the number of preparation phases. However, perhaps there are other considerations and prepared statements are not designed to live that long? 回答1: Prepared statements are so that you can execute repetitive SQL commands which may only differ in