I really don't know how to retrieve a specific row from a pivot table.
Here's my pivot table:
+----+-------------+--------+
| id | peticion_id | tag_id |
+----+-------------+--------+
| 1 | 3 | 15 |
| 2 | 3 | 21 |
| 3 | 3 | 28 |
| 4 | 8 | 21 |
| 5 | 8 | 28 |
| 6 | 44 | 21 |
| 7 | 44 | 28 |
+----+-------------+--------+
I wanna make maybe i think is a dynamic query where for example if i do:
SELECT peticion_id where tag_id in (21,28,15);
The result is:
+-----+-------------+--------+
| id | peticion_id | tag_id |
+-----+-------------+--------+
| 1 | 3 | 15 |
| 2 | 3 | 21 |
| 6 | 44 | 21 |
| 4 | 8 | 21 |
| 3 | 3 | 28 |
| 7 | 44 | 28 |
| 5 | 8 | 28 |
+-----+-------------+--------+
I need the result to be only peticion_id = 3.
I don't know how to formulate the query, maybe I'm looking for the equivalent for(where in) to be an AND clause.
Hope somebody helps.
Thanx
Try this:
SELECT peticion_id
FROM tbl
WHERE tag_id in (21,28,15)
GROUP BY peticion_id
HAVING count(*) = 3
Related
I want to alter or generate Select Query of the Source_Table below at runtime by getting the column total (sum) first then sort according to its result:
Source_Table:
+----+------------+-----------+-----------+-----------+-----------+-----------+
| ID | Name | Field_1 | Field_2 | Field_3 | Field_4 | Field_5 |
+----+------------+-----------+-----------+-----------+-----------+-----------+
| 1 | abc | 10 | 18 | 5 | 21 | 6 |
+----+------------+-----------+-----------+-----------+-----------+-----------+
| 2 | ghq | 22 | 14 | 12 | 11 | 23 |
+----+------------+-----------+-----------+-----------+-----------+-----------+
| 3 | xyz | 35 | 8 | 16 | 7 | 4 |
+----+------------+-----------+-----------+-----------+-----------+-----------+
The Result_Table I am looking at is:
|--------------- sorted fields based on total --------------|
+------------+-----------+-----------+-----------+-----------+-----------+
| Name | Field_5 | Field_3 | Field_4 | Field_2 | Field_1 |
+------------+-----------+-----------+-----------+-----------+-----------+
| abc | 4 | 5 | 21 | 18 | 10 |
+------------+-----------+-----------+-----------+-----------+-----------+
| ghq | 23 | 12 | 11 | 14 | 22 |
+------------+-----------+-----------+-----------+-----------+-----------+
| xyz | 4 | 16 | 7 | 8 | 35 |
+------------+-----------+-----------+-----------+-----------+-----------+
| Total | 31 | 33 | 39 | 40 | 67 | --> get column sum and sort from lowest to highest
+------------+-----------+-----------+-----------+-----------+-----------+
I am not so sure if this is possible with MySQL as I am not able to find good reference in the internet for this case. But I will try..
I have a table like this:
mysql> select * from studentscore;
+------------+-----------+-------+
| student_id | cource_id | score |
+------------+-----------+-------+
| 1 | 1 | 80 |
| 1 | 2 | 90 |
| 1 | 3 | 85 |
| 1 | 4 | 78 |
| 2 | 2 | 53 |
| 2 | 3 | 77 |
| 2 | 5 | 80 |
| 3 | 1 | 71 |
| 3 | 2 | 70 |
| 3 | 4 | 80 |
| 3 | 5 | 65 |
| 3 | 6 | 75 |
| 4 | 2 | 90 |
| 4 | 3 | 80 |
| 4 | 4 | 70 |
| 4 | 6 | 95 |
| 5 | 1 | 60 |
| 5 | 2 | 70 |
| 5 | 5 | 80 |
| 5 | 6 | 69 |
| 6 | 1 | 76 |
| 6 | 2 | 88 |
| 6 | 3 | 87 |
| 7 | 4 | 80 |
| 8 | 2 | 71 |
| 8 | 3 | 58 |
| 8 | 5 | 68 |
| 9 | 2 | 88 |
| 10 | 1 | 77 |
| 10 | 2 | 76 |
| 10 | 3 | 80 |
| 10 | 4 | 85 |
| 10 | 5 | 83 |
| 11 | 3 | 80 |
| 12 | 4 | 99 |
| 13 | 5 | 74 |
+------------+-----------+-------+
I want to show student_id and students' average scores that are higher than 80.
The output I want is like this:
+------------+-------------------+
| student_id | Average |
+------------+-------------------+
| 1 | 83.25 |
| 4 | 83.75 |
| 6 | 83.66666666666667 | // and how can I make this result shorter like 83.67?
| 7 | 80 |
| 9 | 88 |
| 10 | 80.2 |
| 11 | 80 |
| 12 | 99 |
+------------+-------------------+
I've tried the following codes
mysql> select student_id, avg(score) as average_score
-> from studentscore
-> group by student_id
-> where avg(score) >= 80;
and it gave me an syntax error.
I know by rules the where clause should go before the group by clause but I can't because the where clause depends on the result from the group by clause, and if I switch their position it will give me another error("Invalid use of group function").
Can some one tell me how to get the table I want?
use "having" instead of "where"
use having instead of where.
Here's the difference:
with where you can write a predicate that will be applied to each row
with having you can write a predicate that will applied to each group
and in your case, the 2nd is the only solution that can work.
select student_id, avg(score) as average_score
from studentscore
group by student_id
having avg(score) >= 80;
where applies a filter to your data before grouping has taken place, whereas having applies a filter post-grouping. round(,2) will format as you also ask:
select student_id, round(avg(score), 2) as average_score
from studentscore
group by student_id
having average_score >= 80;
This seems like such a simple problem, but I can't find a good solution. I'm trying to select information from a slightly misformatted table. Basically, wherever sequence=0, the person_id should actually be a company_id. This company_id then applies to all the rows which have the same group_id.
Someone thought it was a good idea to format things this way instead of simply having a company_id column, but it makes trying to select by company very difficult. It would make my programming much easier to simply add this extra column, and fix the formatting.
I want to turn something like this:
+----------+------------+-----------+----------+
| group_id | date | person_id | sequence |
+----------+------------+-----------+----------+
| 1 | 2012-08-31 | 10 | 0 |
| 1 | 2012-08-31 | 11 | 1 |
| 1 | 2012-08-31 | 12 | 2 |
| 2 | 1999-04-16 | 10 | 0 |
| 2 | 1999-04-16 | 21 | 1 |
| 2 | 1999-04-16 | 22 | 2 |
| 2 | 1999-04-16 | 23 | 3 |
| 2 | 1999-04-16 | 24 | 4 |
| 3 | 2001-01-09 | 30 | 0 |
| 3 | 2001-01-09 | 31 | 1 |
| 3 | 2001-01-09 | 11 | 2 |
| 3 | 2001-01-09 | 12 | 3 |
+----------+------------+-----------+----------+
Into this:
+------------+----------+------------+-----------+----------+
| company_id | group_id | date | person_id | sequence |
+------------+----------+------------+-----------+----------+
| 10 | 1 | 2012-08-31 | 11 | 1 |
| 10 | 1 | 2012-08-31 | 12 | 2 |
| 10 | 2 | 1999-04-16 | 21 | 1 |
| 10 | 2 | 1999-04-16 | 22 | 2 |
| 10 | 2 | 1999-04-16 | 23 | 3 |
| 10 | 2 | 1999-04-16 | 24 | 4 |
| 30 | 3 | 2001-01-09 | 31 | 1 |
| 30 | 3 | 2001-01-09 | 11 | 2 |
| 30 | 3 | 2001-01-09 | 12 | 3 |
+------------+----------+------------+-----------+----------+
The only way I can think of how to achieve this is with nested SELECT statements, which are very inefficient considering I have about 100M rows. It's a one time fix though, so I don't mind letting it run overnight.
If you permanently want to change your table to include a company_id column then do this:
First alter the table and add the new column:
alter table your_table add company_id int;
Then update all rows to set the company to the person_id = 0 for the group:
UPDATE your_table a
JOIN your_table b ON a.group_id = b.group_id
SET a.company_id = b.person_id
WHERE b.sequence = 0;
And finally remove the rows with sequence = 0:
DELETE FROM your_table WHERE sequence = 0;
Sample SQL Fiddle
The end result will be:
| group_id | date | person_id | sequence | company_id |
|----------|------------|-----------|----------|------------|
| 1 | 2012-08-31 | 11 | 1 | 10 |
| 1 | 2012-08-31 | 12 | 2 | 10 |
| 2 | 1999-04-16 | 21 | 1 | 10 |
| 2 | 1999-04-16 | 22 | 2 | 10 |
| 2 | 1999-04-16 | 23 | 3 | 10 |
| 2 | 1999-04-16 | 24 | 4 | 10 |
| 3 | 2001-01-09 | 31 | 1 | 30 |
| 3 | 2001-01-09 | 11 | 2 | 30 |
| 3 | 2001-01-09 | 12 | 3 | 30 |
My (sub)query results in following dataset:
+---------+------------+-----------+
| item_id | version_id | relevance |
+---------+------------+-----------+
| 1 | 1 | 30 |
| 1 | 2 | 30 |
| 2 | 3 | 22 |
| 3 | 4 | 30 |
| 4 | 5 | 18 |
| 3 | 6 | 30 |
| 2 | 7 | 22 |
| 1 | 8 | 30 |
| 5 | 9 | 48 |
| 4 | 10 | 18 |
| 5 | 11 | 48 |
| 3 | 12 | 30 |
| 3 | 13 | 31 |
| 4 | 14 | 19 |
| 2 | 15 | 22 |
| 1 | 16 | 30 |
| 5 | 17 | 49 |
| 2 | 18 | 22 |
+---------+------------+-----------+
18 rows in set (0.00 sec)
Items and versions are stored in separate InnoDB-tables.
Both tables have auto-incrementing primary keys.
Versions have a foreign key to items (item_id).
My question: How do I get a subset based on relevance?
I would like to fetch the following subset containing the most relevant versions:
+---------+------------+-----------+
| item_id | version_id | relevance |
+---------+------------+-----------+
| 1 | 16 | 30 |
| 2 | 18 | 22 |
| 3 | 13 | 31 |
| 4 | 14 | 19 |
| 5 | 17 | 49 |
+---------+------------+-----------+
It would be even more ideal to fetch the MAX(version_id) in case of equal relevance.
I tried grouping, joining, ordering, etcetera in many ways but I'm not able to get the desired result.
Some of the things I tried is:
SELECT item_id, version_id, relevance
FROM (subquery) a
GROUP BY item_id
ORDER BY relevance DESC, version_id DESC
But of course the ordering happens after the fact, so that both relevance and MAX(version_id) information is lost.
Please advice.
This is how you can do this:
SELECT t1.item_id, max(t1.version_id), t1.relevance FROM t t1
LEFT JOIN t t2 ON t1.item_id = t2.item_id AND t1.relevance < t2.relevance
WHERE t2.relevance IS NULL
GROUP BY t1.item_id
ORDER BY t1.item_id, t1.version_id
Output:
| ITEM_ID | VERSION_ID | RELEVANCE |
|---------|------------|-----------|
| 1 | 16 | 30 |
| 2 | 18 | 22 |
| 3 | 13 | 31 |
| 4 | 14 | 19 |
| 5 | 17 | 49 |
Fiddle here.
i have a table called rc_language_type_table with:
id language
1 english
2 Xhosa
3 afrikaans
etc
then i have a table rc_language_type_assoc_table with:
profile_id | language_type_id |
+------------+------------------+
| 3 | 1 |
| 13 | 1 |
| 15 | 1 |
| 16 | 1 |
where i have profiles and each profile is connected to a language id in a 1 to many
so then i did:
select *,count(*) from rc_language_type_assoc_table group by language_type_id;
+------------+------------------+----------+
| profile_id | language_type_id | count(*) |
+------------+------------------+----------+
| 3 | 1 | 96 |
| 3 | 2 | 19 |
| 3 | 3 | 18 |
| 64 | 4 | 51 |
| 94 | 5 | 10 |
| 37 | 6 | 26 |
| 3 | 7 | 21 |
| 3 | 8 | 4 |
| 3 | 9 | 6 |
| 88 | 10 | 4 |
| 3 | 11 | 3 |
+------------+------------------+----------+
what i want now is: instead having the language_type_id i want to display the actual language...how would i do this please???
i tried:
select *, count(*)
from rc_language_type_assoc_table, rc_language_type_table
group by language_type_id
where rc_language_type_assoc_table.language_type_id = rc_language_type_table.id;
but i get a syntax error...
please help??
thank you
GROUP BY should be "after" the WHERE statement and not before
select *, count(*)
from rc_language_type_assoc_table, rc_language_type_table
where rc_language_type_assoc_table.language_type_id = rc_language_type_table.id
group by language_type_id ;