I have a table with three columns, id, name, and value, as shown below. I want to count the average where the id and value columns are the same, how can I do this?
+----+--------+-------+
| id | name | value |
+----+--------+-------+
| 2 | rahmat | 3 |
| 2 | olive | 5 |
| 3 | sari | 3 |
| 3 | ryan | 2 |
| 1 | zaki | 1 |
+----+--------+-------+
Try using this query:
SELECT AVG(value)
FROM table
WHERE id = value
The output from the sample table you gave in your OP would be 1.5, since sari and zaki are the only 2 users whose records have id and value columns which are equal.
according to your question yes you need to use
SELECT AVG(value)
FROM #table
WHERE id = value
I have created a sqlfiddle here
http://sqlfiddle.com/#!3/9eecb7/4105
from the nature of this question I feel you trying to calculate average of values of those rows having same ids. If that's the case I have created another fiddle http://sqlfiddle.com/#!3/9eecb7/4110 where you need to use group by
select id, sum(value)/count(id) as average from #table group by id
Lemme know if it is something you are after or you need something else.
Related
i have database like this
============================
| id | name | value | key |
============================
| 1 | sara | | 1 |
============================
| 2 | sara | | 1 |
============================
| 3 | sara | 1 | |
============================
| 4 | jhon | | 1 |
============================
| 4 | jhon | 1 | |
============================
i want first to get only one result for each name
my expected output
jhon
sara
i use
select * from my_table
but it's display all names
and need to sort table by key cell
my expected output with sort
sara (3 keys)
jhon (1 key)
The function you are searching is called group by.
SELECT name, SUM(key) FROM my_table GROUP BY name
You can also use other aggregate function (not only SUM), maybe you want
SELECT name, COUNT(*) FROM my_table GROUP BY name
SELECT name, COUNT(key) FROM my_table GROUP BY name
Search for some examples for group by (also here on Stack Overflow) and check out the different results.
The other function you are searching for is called order by.
Please read some book or tutorials about sql, this is pretty basic stuff.
Ok so a bit of a funny question here. I have two tables: -
LiveTable
ArchiveTable
The data is as follows: -
Table: LiveTable Table: ArchiveTable
| ID | NAME | | ID | NAME |
------------------ ------------------
| 1 | Test One | | 4 | Test Four |
------------------ ------------------
| 2 | Test Two | | 5 | Test Five |
------------------ ------------------
| 3 | Test Three| | 6 | Test Six |
What I want to do is merge them into one table for querying purposes only. Not as a Database Structure.
In essence when I do a PHP Loop I want the results to work like this: -
Merged Results
| ID | NAME |
------------------
| 1 | Test One |
------------------
| 2 | Test Two |
------------------
| 3 | Test Three|
------------------
| 4 | Test Four |
------------------
| 5 | Test Five |
------------------
| 6 | Test Six |
How would I go about doing this? Also is there a way of doing this with Doctrine?
You can use an SQL query with UNION:
SELECT ID, Name
FROM LiveTable
UNION ALL
SELECT ID, Name
FROM ArchiveTable
Note: UNION ALL will retain duplicates. If you want to remove duplicate records, then use UNION.
Yould use UNION:
SELECT id, name FROM tbl1
UNION ALL
SELECT id, name FROM tbl2
Create DB view using above two tables
CREATE VIEW view_name AS SELECT
id, name FROM tbl1
UNION
id, name FROM tbl2
Then you can query on your view
you can use the sql query multi table select
Select * from LiveTable,ArchiveTable
that's it
i have this table structure "posts"
+----+-------+---------------+
| id | post | authors_ids |
+----+-------+---------------+
| 1 | test1 | ["1","2"] |
+----+-------+---------------+
| 2 | test2 | ["1","3"] |
+----+-------+---------------+
| 3 | test3 | ["3","4","5"] |
+----+-------+---------------+
what i want to do is to select rows that contains in authors_ids field a particular value for example i need to select the posts where authors_ids array contains number 4
i know that the table structure is wrong but at this time i will not be able to change it.
how can i achieve that ?
One quick way to achieve this would be to select using LIKE:
SELECT * FROM `posts` WHERE `authors_ids` LIKE '%"4"%';
My table User
+----+-----------+---------+--------+---------+------+-------+
| id | name | email | number | call_no | chek | Extra |
+----+-----------+-------+----------+---------+------+-------+
| 1 | one | a#a.com | 123 | 1164 | 1 | 1,2 |
+----+-----------+---------+---------+---------+------+------+
| 2 | two | a#a.com | 123 | 1164 | 1 | 2,1 |
+----+-----------+---------+---------+---------+------+------+
I have the field called Extra it contains the value 1,2
what is my question is ?
I need to match the 1,2 in the table id and myresult like one,two from the user table
For simple example query.what im tried is in below ?
select name from user Extra in('1,2');
My expected output is
one,two
If i tried to do in explode and if i run it in loop i can get the result but i need this in sql is it possible to get it?
You should have a separate table with one row per id and each value of extra. This is called a junction table. SQL has a great data structure for storing lists of things, called a table not a string. And, storing numbers as characters is even worse.
You can, however, do what you want with a join and aggregation:
select id, group_concat(e.name) as names
from table t left join
table e
on find_in_set(t.id, e.extra) > 0
group by t.id;
This is an example MYSQL result
+----+---+
| A | B |
+----+---+
| 1 | 1 |
| 1 | 2 |
| 2 | 3 |
| 2 | 4 |
| 3 | 5 |
+----+---+
I would like to run through every distinct in Column A and do something utilizing the values in Column B.
Let's say A has userids and B has foods. I would like to grab all the foods that user 1 likes and then shoot an email to 1, then grab all the foods that user 2 likes and email to her, and so forth. Would appreciate any suggestions.
If you want comma separated values, you can use GROUP_CONCAT
SELECT A, GROUP_CONCAT(DISTINCT B) foodList
FROM tableName
GROUP BY A
SQLFiddle Demo
Other Link
GROUP BY clause