How to join different tables with pivote table
I have 4 tables like
users
id | name |
-------------
1 | abc |
2 | ccc |
user_profile
id | user_id | email |
-------------------------------
1 | 1 | abc#gmail.com
2 | 2 | ccc#gmail.com
skills
id | skill_name |
--------------------------
1 | java |
2 | php |
user_skills
user_id | skill_id |
---------------------------
1 | 1 |
1 | 2 |
2 | 1 |
The result should be
name | email | skills |
----------------------------------
abc |abc#gmail.com | java, php |
ccc |ccc#gmail.com | java |
I am able to join multiple tables but I have problem joining pivote
I have tried below with query
SELECT users.name,user_profiles.email, group_concat(programs.name)
from users
JOIN user_profiles on user_profiles.user_id = users.id
LEFT JOIN user_skills on user_skills.user_id = users.id
LEFT JOIN skills on user_skills.skill_id = skills.id
GROUP BY users.id
Can anyone help me on this please??Thanks
You need GROUP_CONCAT to generate the CSV list of skills:
SELECT
u.name,
up.email,
GROUP_CONCAT(s.skill_name) AS skills
FROM users u
INNER JOIN user_profile up
ON u.id = up.user_id
LEFT JOIN user_skills us
ON u.id = us.user_id
INNER JOIN skills s
ON us.skill_id = s.id
GROUP BY
u.id, u.name, up.email;
Demo
Note that I group by both the user's id and name, because perhaps two users happen to have the same name. Follow the link below for a running SQLFiddle.
Your query should work. Perhaps the problem is the reference to programs rather than skills:
select u.name, up.email, group_concat(s.name)
from users u join
user_profiles up
on up.user_id = u.id left join
user_skills us
on us.user_id = u.id left join
skills s
on us.skill_id = s.id
group by u.name, up.email;
Related
My case looks simple but i'm messing around with this..
I have 4 tables: User, Macros, Categories, and another one that relate users with categories. One Macro have many Categories.
What i need, is a query that based on the Macro, get the users and the Categories where user is NOT IN.
Example: I have a macro named VEICULES, with categories CAR,TRUCK and Motorcycle. User José is on category CAR and User Julio on category CAR and TRUCK, so my query should return:
José | TRUCK,Motorcycle
Julio | Motorcycle
Tables:
prd_users
id | name | Email
---------------------------
1 | José | jose#email.com
2 | Júlio | julio#email.com
3 | André | andre#email.com
cat_macros
macro_id | macro_name
-----------------------
1 | Veicules |
cat_categories
category_id | category_name | macro_id
---------------------------------------
1 | Cars | 1
2 | Trucks | 1
3 | Motorcycles | 1
prd_tr_rabbit_catg
id | category_id | tasker_user_id
---------------------------------------
1 | 1 | 1
2 | 1 | 2
3 | 2 | 2
I'm stucked on just getting the categories where the user already is ..
SELECT prd_users.id, prd_users.name,
prd_users.email,cat_macros.macro_name as macro,
GROUP_CONCAT(cat_categories.category_name SEPARATOR ', ') as in_categories
FROM prd_users
INNER JOIN prd_tr_rabbit_catg ON prd_tr_rabbit_catg.tasker_user_id = prd_users.id
INNER JOIN cat_categories ON cat_categories.category_id = prd_tr_rabbit_catg.category_id
INNER JOIN cat_macros ON cat_macros.macro_id = cat_categories.macro_id
WHERE cat_macros.macro_id = '45'
GROUP BY prd_users.id;
To solve this problem it's necessary to create a list of all users joined with all categories for the given macro category. This can be done with a CROSS JOIN:
SELECT *
FROM prd_users u
CROSS JOIN (SELECT m.macro_id, m.macro_name, c.category_name, c.category_id
FROM cat_macros m
JOIN cat_categories c ON c.macro_id = m.macro_id) c
This can then be LEFT JOINed to the prd_tr_rabbit_catg table and by selecting those rows where there is no matching entry in the prd_tr_rabbit_catg table, we can find the users who don't have an entry for the given category:
SELECT c.macro_name, u.id AS user_id, u.name, u.Email, GROUP_CONCAT(c.category_name) AS missing_cats
FROM prd_users u
CROSS JOIN (SELECT m.macro_id, m.macro_name, c.category_name, c.category_id
FROM cat_macros m
JOIN cat_categories c ON c.macro_id = m.macro_id) c
LEFT JOIN prd_tr_rabbit_catg x ON x.tasker_user_id = u.id AND x.category_id = c.category_id
WHERE x.id IS NULL
AND c.macro_id = 1
GROUP BY c.macro_name, u.id
For your sample data, this gives:
macro_name user_id name Email missing_cats
Veicules 1 José jose#email.com Motorcycles,Trucks
Veicules 2 Júlio julio#email.com Motorcycles
Veicules 3 André andre#email.com Cars,Motorcycles,Trucks
Update
To exclude users who don't have any of the categories, add a HAVING clause:
HAVING COUNT(*) < (SELECT COUNT(*) FROM cat_categories WHERE macro_id = 1)
Demo on SQLFiddle
Suppose I have a table named users consist of columns: user_id, user_name, user_created_by.
+------------------+----------------------+-------------------+
| user_id + user_name + user_created_by +
+------------------+----------------------+-------------------+
| 1 | John | 1 |
| 2 | Ann | 1 |
| 3 | Paul | 2 |
| 4 | King | 2 |
| 5 | Dirk | 3 |
+------------------+----------------------+-------------------+
The value of user_created_by is the user_id who created that record. Now, I want to make a query that results one specific row with added column let's say user_created_by_name which is the user_name of the user_id from the user_created_by. Suppose we want to get "Paul"'s record with who (the name) create it (temporary new column). For ease of understanding this is my expected result:
+----------+--------------+-------------------+------------------------+
| user_id | user_name | user_created_by | user_created_by_name |
+----------+--------------+-------------------+------------------------+
| 3 | Paul | 2 | Ann |
+----------+--------------+-------------------+------------------------+
this is my query using codeigniter:
$query=$this->db->query("SELECT *,
(SELECT user_name FROM users WHERE user_id = user_created_by)
AS "user_created_by_name" FROM users WHERE user_id=3);
But my result are:
+----------+--------------+-------------------+------------------------+
| user_id | user_name | user_created_by | user_created_by_name |
+----------+--------------+-------------------+------------------------+
| 3 | Paul | 2 | NULL |
+----------+--------------+-------------------+------------------------+
You culd use a self join (join the same table two time) using alias for fere to the tables as different sets of data
SELECT a.user_id, a.user_name, a.user_created_by, b.user_name as user_created_by_name
from users a
inner join user b on a.user_created_by = b.user_id
where a.user_id = 3
use self join
select u1.user_id, u1.name as user_name,
u2.user_created_by
,u2.user_name as createdby from users u1
join users u2 on u1.user_id=u2.user_created_by
where u1.user_id=3
You can solve this problem using a JOIN.
$sql = "SELECT users.user_id, users.user_name, user_created_by_name.user_name,
FROM users JOIN users AS user_created_by_name ON users.user_id = user_created_by_name.user_id WHERE users.user_id = 3";
$query=$this->db->query($sql);
If you you have users that were not created by another user use a LEFT JOIN instead:
$sql = "SELECT users.user_id, users.user_name, user_created_by_name.user_name,
FROM users LEFT JOIN users AS user_created_by_name ON users.user_id = users.user_id WHERE user_created_by_name.user_id = 3";
$query=$this->db->query($sql);
This will work:
SELECT a.user_id as User_id,
a.user_name as Name,
b.user_id as Created_by_user_id,
b.user_name as Created_by_name
FROM users AS a
INNER JOIN users AS b
ON a.user_id = b.user_created_by
WHERE a.user_id = 3
It is called a self-join, which is used when combining two records of the same table.
Say I have two tables: FRUITS and USERS.
fruits
-------------
id | name |
-------------
1 | Apple |
2 | Orange |
3 | Pear |
-------------
users
-------------------
id | name | fruit |
-------------------
1 | John | 3 |
2 | Bob | 2 |
3 | Adam | 1 |
-------------------
I use the below query (answered in this question) to query users with a proper fruit name instead of just fruit ID:
SELECT u.id, u.name, f.name FROM users u JOIN fruits f ON u.fruit = f.id
However the above query only returns users with a valid fruit ID. How to modify this query to also return users with invalid/empty fruit ID? That way fruit name should be NULL.
Use a 'LEFT JOIN':
SELECT
u.id
,u.name
,f.name FROM
users u
LEFT JOIN fruits f ON u.fruit = f.id
Use left join
SELECT
u.id,
u.name,
f.name
FROM users u
LEFT JOIN fruits f ON u.fruit = f.id
You would use a left join:
SELECT u.id, u.name, f.name
FROM users u LEFT JOIN
fruits f
ON u.fruit = f.id;
This will keep all rows in the users table, even those with non-matching values in fruits.
SELECT u.id, u.name, f.name FROM users u
LEFT JOIN fruits f ON u.fruit = f.id
Read about LEFT JOIN here.
I am new to this kind of relational type of database design. I just designed the database in this manner. However, I am quite confused on this JOIN of MySQL. What should be my query to join all this table. If you can see the table users is the reference of all the tables.
users
+----------+----------------+-----------------+
| users_id | users_level_id | users_status_id |
+----------+----------------+-----------------+
| 1 | 1 | 1 |
| 2 | 2 | 1 |
+----------+----------------+-----------------+
users_credentials
+----------+---------------------------+-----------------------------+----------------------------+
| users_id | users_credential_username | users_credential_email | users_credential_password |
+----------+---------------------------+-----------------------------+----------------------------+
| 1 | super | super#gmail.com | $5$e94e9e$vptscyHjm8rdX0j6 |
| 2 | admin | admin#gmail.com | $5$fVuOmySyC0PttbiMn8in0k7 |
+----------+---------------------------+-----------------------------+----------------------------+
users_level
+----------------+-------------------------+
| users_level_id | users_level_description |
+----------------+-------------------------+
| 1 | Super Administrator |
| 2 | Administrator |
+----------------+-------------------------+
users_status
+-----------------+--------------------------+
| users_status_id | users_status_description |
+-----------------+--------------------------+
| 0 | Disabled |
| 1 | Enabled |
+-----------------+--------------------------+
Try this
SELECT u.*, uc.*, ul.*, us.*
FROM users u
INNER JOIN users_credentials uc
ON u.users_id = uc.users_id
INNER JOIN users_level ul
ON u.users_level_id = ul.users_level_id
INNER JOIN users_status us
ON u.users_status_id = us.users_status_id
Note the use INNER JOIN: this means that if a user does not have corresponing record on joined table it won't be shown; if you need to return every user even without matching record on related tables, change INNER JOIN with LEFT JOIN.
EDITED after user comment:
If you want to return just some column, define it as this example
SELECT uc.users_credential_username AS username,
uc.users_credential_email AS email,
uc.users_credential_password AS pwd,
ul.users_level_description AS level,
us.users_status_description AS status
This is a simple query that will join all of them
select *
from users
left join users_credentials
on users_credentials.users_id = users.users_id
left join users_level
on users_level.users_level_id = users.users_level_id
left join users_status
on users_status.users_status_id = users.users_status_id
EDIT
if you want to fetch data from different tables
user this
select users.* , users_credentials.* , users_level.* , users_status.*
from users
left join users_credentials
on users_credentials.users_id = users.users_id
left join users_level
on users_level.users_level_id = users.users_level_id
left join users_status
on users_status.users_status_id = users.users_status_id
I think this look like this :
SELECT * FROM users
LEFT JOIN user_credentials ON users.user_id = user_credential.user_id
LEFT JOIN user_level ON users.users_level_id = users_level.users_level_id
and so on..
Use this type of query....
SELECT c.*, l.*, s.*
FROM users AS u
INNER JOIN users_credentials AS c ON (u.users_id = C.users_id)
INNER JOIN users_level AS l ON (u.users_level_id= l.users_level_id)
INNER JOIN users_status AS s ON (u.users_status_id= s.users_status_id)
Where you can specify the field what you want in .* ...
Join is used to fetch data from normalized tables which have foreign key relation with the reference table.
For the above table with join you can fetch data among two tables with the help of reference table.
For example
Select * from users a JOIN users_credentials b
ON a.user_id=b.user_id JOIN users_level c
ON c.users_level_id=a.users_level_id
where users_credential_username='super';
The result of this query will give you the detail like users_level_description for the user with users_credential_username=super.
I have three columns I need to join which comes from 3 different tables,
Contributions table:
+-----------+---------------------+
| record_id | contributor_user_id |
+-----------+---------------------+
| 1 | 2 |
+-----------+---------------------+
| 1 | 5 |
+-----------+---------------------+
Members table:
+--------------+---------+
| username | user_id |
+--------------+---------+
| Test | 1 |
+--------------+---------+
| Test2 | 5 |
+--------------+---------+
| Test3 | 6 |
+--------------+---------+
Records table:
+---------+-----------+
| user_id | record_id |
+---------+-----------+
| 28 | 1 |
+---------+-----------+
For what I need to return is the username and user_id for displaying the record owner. Also, display the username and the user_id, but this can be multiple (more than 1+ user). I've tried this:
SELECT usr.username,
usr.user_id,
rec.record_id,
contrib.record_id,
contrib.contributor_user_id
FROM
(
records rec
INNER JOIN members usr ON rec.user_id = usr.user_id
# this returns records as NULL
LEFT OUTER JOIN contributions contrib ON rec.record_id = contrib.record_id AND contrib.contributor_user_id = usr.user_id
# this works, but I need the username to be displayed too
LEFT OUTER JOIN contributions contrib ON rec.record_id = contrib.record_id
)
WHERE rec.record_id = 1
Try nesting the join for contributing users inside of the left join to contributions.
SELECT u.username, u.user_id, r.record_id, u2.username as ContributorName, u2.user_id as ContributorId
FROM records r
INNER JOIN members u
ON r.user_id = u.user_id
LEFT JOIN contributions c
INNER JOIN members u2
ON c.contributor_user_id = u2.user_id
ON r.record_id = c.record_id
WHERE r.record_id = 1
SELECT
usr.username AS record_owner
, usr.user_id AS record_owner_id
, rec.record_id
, con.contributor_user_id AS contributor_id
, contributors.username AS contributor_name
FROM
records rec
INNER JOIN
members usr
ON rec.user_id = usr.user_id
LEFT OUTER JOIN
contributions con
ON rec.record_id = con.record_id
INNER JOIN
members contributors
ON con.contributor_user_id = contributors.user_id
WHERE
rec.record_id = 1