The group-by tag has no wiki summary.
2
votes
2answers
78 views
Why does adding LIMIT to my query make it crawl?
Simple query:
select sum(score) total,name,gender,dob,country
from users join scores on users.id = scores.user_id
where date between '2012-01-01' and '2012-01-31 23:59:59'
group by scores.user_id ...
1
vote
2answers
51 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 ...
1
vote
0answers
28 views
Repeated values in group_concat
I have two tables, first the table food and Second is Activity:
INSERT INTO food
(`id`, `foodName`)
VALUES
(1, 'food1'),
(2, 'food2'),
(3, 'food3'),
(4, 'food4'),
(5, ...
0
votes
1answer
49 views
WITH ROLLUP WHERE NULL = x
I tried to find this question somewhere else on here, and found a couple that were similar to it -- but all the answers seemed pretty convoluted, and I think it was surprising to me because I just ...
1
vote
1answer
70 views
GROUP BY with OR/AND clause?
Lets say my database looks like this:
Table: messages
+----+------+----+----------+----------+
| id | from | to | double_1 | double_2 |
+----+------+----+----------+----------+
| 1 | 1 ...
0
votes
1answer
78 views
Error “column does not exist” in a SELECT with JOIN and GROUP BY querry
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
4answers
129 views
Delete the N oldest entries grouped by multiple columns
I´d like to delete the oldest entries of my database, but in each category shall remain at least N words of each char.
Structure of TABLE words
id | word | char | category
For example I have the ...
2
votes
2answers
68 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
370 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
98 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 ...
1
vote
1answer
48 views
Avoiding performance hit from GROUP BY during FULLTEXT search?
Is there any clever way to avoid the performance hit from using group by during fulltext search?
SELECT p.topic_id, min(p.post_id)
FROM forum_posts AS p
WHERE MATCH (p.post_text) AGAINST ('baby ...
2
votes
2answers
97 views
Slow MySQL query with Order and Group by
I have a query that is taking a long time to execute (1.13s). The two tables user_articles and articles have around 25,000 records. This is the query:
SELECT `user_articles`.*
FROM `user_articles`
...
3
votes
3answers
181 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 ...
0
votes
1answer
141 views
Group By on column from joined table
its about the following query.
EXPLAIN SELECT phrase, infinitiv
FROM `dict_verbs_all` `t`
INNER JOIN `dict_verbs_all_language` `verbsGerman_c`
ON (`t`.`id`=`verbsGerman_c`.`verb_id`)
INNER JOIN ...
5
votes
2answers
222 views
T-SQL Purpose of MAX in this Group By Query
I have run into some pre-existing SQL that I'm having a hard time uderstanding.
SELECT
MAX(I.Symbol) Symbol
, MAX(I.Ticker) CUSIP
, MAX(I.Name) Name
, SUM(H.Quantity) TotalQuantity
, ...
