GROUP BY : SQL Aggregation for Common Values

learn more… | top users | synonyms

0
votes
2answers
46 views

sqlite group_concat error while executing query

I have table: CREATE TABLE www ( Col_1 VARCHAR, Col_2 VARCHAR ); select count(*) from www; --1496 And I have error: "Error while executing query: aggregate function are not allowed in ...
0
votes
1answer
12 views

Filter and then sort products by availability

I have table with products. Each product can be avaible in 1+ suppliers, so product can be present multiple times. products - id_productSupplier (primary key) - id_product (foreign key) - ...
0
votes
1answer
65 views

How to optimize a very slow query with joins and group by?

I have this GTFS database : All the ***_id columns are indexed, and there are foreign keys between tables (such as a FK on trips.route_id to routes.route_id). So basically the link between a stop ...
0
votes
1answer
21 views

MySQL order of query

My query return like this. 12 14 14 99 78 78 54 I want result to be sorted so that no same number comes consecutively in the result. The result that I want is like this. 12 14 99 14 78 54 78
0
votes
1answer
76 views

sql server Group by with calculated values

I have two tables: costumer table and invoice table. How to calculate sum(value) for each costumer (id) when I have calculated variables in group by statement - without puting code for calculated ...
0
votes
1answer
99 views

GROUP BY performance

I have a query like this: SELECT HOUR(datetime) as Hour, COUNT(*) as hits, SUM(clicks) FROM visitors_log_table WHERE datetime >= CURDATE() GROUP BY Hour WITH ROLLUP It works fine. But I ...
-1
votes
1answer
74 views

Select latest record for each ID

I have three tables that contains data as below: Users Id Name Other_Columns --------------------------- 1 John Blah 2 Ricky Blah 3 Stella Blah 4 Bob Blah Saldo Id ...
1
vote
0answers
18 views

Grouping results with left and inner join with zero counts

I have a query like SELECT `campaign_question_options`.`text`, COUNT(`campaign_submission_answers`.`answer`) as `count` FROM `campaign_questions` INNER JOIN ...
1
vote
0answers
44 views

Selecting most recent date when dates are stored in another table

Working in a MySQL database, I have tables set up like this: Table song_instances has song_id (int), meeting_instance_id (int) The meeting_instances table has columns meeting_instance_id (int), ...
1
vote
0answers
68 views

GROUP BY multiple columns

I'm trying to draw stats out of a table and depending on the increment, group them by year, month, date. The table is as follows CREATE TABLE `channel_stats` ( `channel_id` int(10) unsigned ...
1
vote
0answers
100 views

How to index for a group by with columns from different tables?

Is it possible to create an index from columns of 2 different tables? If not, how do we optimize a query that does a group by on columns of 2 different tables? For example: the following ...
1
vote
0answers
278 views

MySQL GROUP BY and ORDER BY giving inconsistent results

I'm currently working with WordPress, and I've added a new meta value which is a number between 0 and 30. Zero is ignored and up to 30 need to be organised in order and only the latest (based on the ...
0
votes
0answers
11 views

MySQL GROUP BY performance not improved by 1-column vs 2-column condition

mySQL 5.6.22 on 32GB RAM CentOS I was very surprised that this change did not improve GROUP BY performance. It's a query with multiple joins, of course run with SQL_NO_CACHE option. In my original ...
0
votes
0answers
11 views

Sum of nested group query

I'm very new to SQL, so please bear suggest improvements anywhere. I have a PaymentsReceived table like this (simplified to only what is relevant) AccountID refrerences Accounts(ID) PaymentDate ...
0
votes
0answers
29 views

Mysql sum of column group by question

I have the results of a select that I am joining on that I need to get a slightly complex sum of a column from. I need the sum of result grouped on id PLUS the sum of result of any row where ...
0
votes
0answers
47 views

mysql select latest per group using 2 different tables along with self join

I have a query SQL Fiddle which contains 2 tables tbl_data CREATE TABLE tbl_data ( id int(10) unsigned NOT NULL, type varchar(32) NOT NULL DEFAULT '', title varchar(255) NOT NULL DEFAULT ...
0
votes
0answers
30 views

Generate report from visitor counter

I have a visitor counter, the table looks like this: id | country_code | datetime | Browser | ... --------------------------------------------------------- 1 | FR | ...
0
votes
0answers
283 views

group by and order by making query very slow in mysql?

Query works fast: select SQL_NO_CACHE users.id, users.name from useres left join user_statistics on users.id = user_statistics.user_id where users.is_deleted = 0 group by users.id ...
0
votes
0answers
43 views

Is it possible to group by a fraction of the result set?

I have a database of products with prices. What I'd like to be able to do is figure out 5 different price ranges such that each range, when ordered by price, will have approximately the same number of ...
0
votes
0answers
55 views

How can I number my groups using an Access “Find Duplicates” Query?

I have a query created by the MS Access 2010 find duplicates wizard. It is: SELECT * FROM fbExpenses WHERE [expense_date] In (SELECT [expense_date] FROM [fbExpenses] As ...
0
votes
0answers
137 views

Select Foo object without any specific Bar events

Consider two tables: Foo: id INT, name VARCHAR Bar: id INT, foo_id INT REFERENCES Foo(id), event_type VARCHAR DEFAULT NULL, event_duration INT DEFAULT NULL Each Foo item can have ...
0
votes
0answers
80 views

is it good to add index on column used in group by clause?

I have a query like- select x, sum(y) from xyz where z>=100 group by x order by sum(y) desc; will it be faster if I am going to add index on x?
0
votes
0answers
91 views

can this mysql query be optimized further?

I have this query select counterparty_id, max(id) max_id from client_administrations where counterparty_type = 1 and effective_on <= '2013-10-22' group by counterparty_id When I ...
-2
votes
0answers
32 views

Multiply operation/field causing the record set to 'ungroup'?

I'm trying to sort a query for a report but every time I add a Multiply operation to it the record set result becomes a mess and if I try to GROUP BY I get the legendary ...either an aggregate ...