Tagged Questions
1
vote
2answers
67 views
Group Database Entries by time difference
I have a large postgreSQL database with log data. All this data has timestamps and I want to group consecutive rows where the difference between the timestamps is less then 1500 miliseconds for ...
0
votes
1answer
133 views
Error “column does not exist” in a SELECT with JOIN and GROUP BY query
I'm using PostgreSQL 9.1 with a Ruby on Rails application.
I'm trying to list the last version of each "charge" (in my history table : hist_version_charges) belonging to the same project id ...
2
votes
2answers
93 views
Postgres: Use result of group by as column names
I have a messages table in a database, which include a sender id and a message type (and of course many more columns not relevant for this question). I try to create a query which counts how many ...
6
votes
6answers
478 views
Find “n” consecutive free numbers from table
I have some table with numbers like this (status is either FREE or ASSIGNED)
id_set number status
-----------------------
1 000001 ASSIGNED
1 000002 FREE
1 000003 ...
1
vote
1answer
134 views
postgres GROUP BY and ORDER BY problem
I have two tables like this:
CREATE TABLE cmap5 (
name VARCHAR(2000),
lexemes TSQUERY
);
and
CREATE TABLE IF NOT EXISTS synonyms_all_gin_tsvcolumn (
cid int NOT NULL ...
3
votes
3answers
236 views
PostgreSQL 8.3: Slow GROUP BY on large table
I have a table with about 10 million records. I want to do a simple group by, but it's using a sequential scan and is slow...
select run_id, count(*) from result group by run_id;
I have an index ...
2
votes
3answers
465 views
Slow query on large table with GROUP BY and ORDER BY
I have a table with 7.2 million tuples which looks like this:
table public.methods
column | type | attributes
...
