Finding rank of a single record - Mailing list pgsql-general
From | Alexander Farber |
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Subject | Finding rank of a single record |
Date | |
Msg-id | AANLkTi=MsRjjY4RS41xbpSULm=vs5JeE-hb8mve29w+g@mail.gmail.com Whole thread Raw |
Responses |
Re: Finding rank of a single record
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List | pgsql-general |
Hello, I have 2 tables with user infos (please see \d output at the bottom) and would like to find their rank depending on their "money". When I select all records, the rank() works fine: pref=> select u.first_name, u.city, m.money, rank() over (order by money desc) from pref_users u, pref_money m where m.yw=to_char(current_timestamp, 'YYYY-IW') and u.id=m.id; first_name | city | money | rank ------------------------------+---------------------------------+-------+------ Александр | Сызрань | 2169 | 1 jorj | | 1955 | 2 Сергей | 158 | 1948 | 3 Алексей | 1505941 | 1060 | 4 Борис | Холон | 1034 | 5 сергей | | 1012 | 6 ..................... But when I try to select a single record, then I always get the rank 1: pref=> select u.id, u.first_name, u.city, m.money, rank() over (order by money desc) from pref_users u, pref_money m where m.yw=to_char(current_timestamp, 'YYYY-IW') and u.id=m.id and u.id='OK138239987797'; id | first_name | city | money | rank ----------------+------------+-------------+-------+------ OK138239987797 | Иван | Новосибирск | 468 | 1 (1 row) (I guess because my "window" is 1 row only) Please give me a hint how to select just 1 record and still find it's correct rank compared to other. Or do I have to introduce a 3rd table holding ranks and update it by a cronjob? Regards Alex P.S. the 2 tables are: pref=> \d pref_users; Table "public.pref_users" Column | Type | Modifiers ------------+-----------------------------+--------------- id | character varying(32) | not null first_name | character varying(32) | last_name | character varying(32) | female | boolean | avatar | character varying(128) | city | character varying(32) | lat | real | lng | real | last_login | timestamp without time zone | default now() last_ip | inet | medals | smallint | Indexes: "pref_users_pkey" PRIMARY KEY, btree (id) Check constraints: "pref_users_lat_check" CHECK ((-90)::double precision <= lat AND lat <= 90::double precision) "pref_users_lng_check" CHECK ((-90)::double precision <= lng AND lng <= 90::double precision) "pref_users_medals_check" CHECK (medals > 0) Referenced by: TABLE "pref_misere" CONSTRAINT "pref_misere_id_fkey" FOREIGN KEY (id) REFERENCES pref_users(id) TABLE "pref_money" CONSTRAINT "pref_money_id_fkey" FOREIGN KEY (id) REFERENCES pref_users(id) TABLE "pref_pass" CONSTRAINT "pref_pass_id_fkey" FOREIGN KEY (id) REFERENCES pref_users(id) TABLE "pref_rate" CONSTRAINT "pref_rate_obj_fkey" FOREIGN KEY (obj) REFERENCES pref_users(id) TABLE "pref_rate" CONSTRAINT "pref_rate_subj_fkey" FOREIGN KEY (subj) REFERENCES pref_users(id) pref=> \d pref_money; Table "public.pref_money" Column | Type | Modifiers --------+-----------------------+----------------------------------------- id | character varying(32) | money | integer | not null yw | character(7) | default to_char(now(), 'YYYY-IW'::text) Indexes: "pref_money_yw_index" btree (yw) Foreign-key constraints: "pref_money_id_fkey" FOREIGN KEY (id) REFERENCES pref_users(id)
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