I have a 2 tables:
People table:
id | name | date
1 | Mika | 2013
2 | Rose | 2015
Work table:
id | user_id | work_name | registers
1 | 1 | rugby | 10
2 | 1 | golf | 3
I use this query to join tables:
SELECT * FROM work INNER JOIN people ON work.user_id = people.id WHERE work_name= :work_name
This work it, but I get duplicate column ID and in php when I try to print the camp id, this show the last column id..
I try with this but dont work it:
SELECT *, id AS 'work_id'
FROM work
INNER JOIN people ON work.user_id = people.id
WHERE work_name= :work_name
That is because you are using * in the SELECT that mean will bring all the fields from boths tables instead you can use
SELECT work.id as work_id,
work.name as work_name,
work.date as work_date,
people.id as people_id,
people.name as people_name,
people.date as people_date
Try to manually list all of columns you need to display, for instance
SELECT w.user_id, w.work_name, w.registers, p.name, p.date FROM work as w INNER JOIN people as p ON work.user_id = people.id WHERE work_name= :work_name
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
I've been trying for two days, without luck.
I have the following simplified tables in my database:
customers:
| id | name |
| 1 | andrea |
| 2 | marco |
| 3 | giovanni |
access:
| id | name_id | date |
| 1 | 1 | 5000 |
| 2 | 1 | 4000 |
| 3 | 2 | 1500 |
| 4 | 2 | 3000 |
| 5 | 2 | 1000 |
| 6 | 3 | 6000 |
| 7 | 3 | 2000 |
I want to return all the names with their last access date.
At first I tried simply with
SELECT * FROM customers LEFT JOIN access ON customers.id =
access.name_id
But I got 7 rows instead of 3 as expected. So I understood I need to use GROUP BY statemet as the following:
SELECT * FROM customers LEFT JOIN access ON customers.id =
access.name_id GROUP BY customers.id
As far I know, GROUP BY combines using a random row. In fact I got unordered access dates with several tests.
Instead I need to group every customer id with its corresponding latest access! How this can be done?
You have to get the latest date from the access table with a group by on the the name_id, then join this result with the customer table. Here is the query:
select c.id, c.name, a.last_access_date from customers c left join
(select id, name_id, max(access_date) last_access_date from access group by name_id) a
on c.id=a.name_id;
Here is a DEMO on sqlfiddle.
I think this is what you'd like to achieve:
SELECT c.id, c.name, max(a.date) last_access
FROM customers c
LEFT JOIN access a ON c.id = a.name_id
GROUP BY c.id, c.name
The LEFT join will return all entries in table customers regardless if the join criteria (c.id = a.name_id) is satisfied. This means that you might get some NULL entries.
Example:
Simply add a new row in the customers table (id: 4, name: manuela). The output will have 4 rows and the newest row will be (id: 4, last_access: null)
I would do this using a correlated subquery in the ON clause:
SELECT a.*, c.*
FROM customers c LEFT JOIN
access a
ON c.id = a.name_id AND
a.DATE = (SELECT MAX(a2.date) FROM access a2 WHERE a2.name_id = a.name_id);
If this statement is true:
I need to group every customer id with its corresponding latest access! How this can be done?
Then you can simply do:
select a.name_id, max(a2.date)
from access a
group by a.name_id;
You do not need the customers table because:
All customers are in access, so the left join is not necessary.
You need no columns from customers.
I have what can only be described as a seemingly simple problem with most likely a simple solution; yet that simple solution escapes me. I've searched and trudged through the vast web of StackOverflow only to come up short finding only solutions that seem to be extremely complex. I've already kind of solved this problem, but, it's disgusting and I'm ashamed of it. Surely there is a better way, for there must be a Knight in shining MySQL armor wielding a query sword who can come up with a simple and elegant solution. Here goes:
For the sake of this question, we'll keep the two tables simple.
Table 1
users (user_id, active, name)
and
Table 2
user_projects (user_project_id, user_id, start_date, details)
In this case, records for users are added as needed. Related records are then added as projects are completed by users.
My question is: Using a query, how can I get 1 record containing all of the information in table 1 active users joined with the record from table 2 with the most recent date based on start_date?
In other words, if I have this:
| user_id | active | name |
| 1 | 1 | brian |
and this:
| user_project_id | user_id | start_date | details |
| 1 | 1 | 2013-10-02 | proj 1 |
| 2 | 1 | 2013-11-26 | proj 2 |
| 3 | 1 | 2014-01-02 | proj 3 |
produce the query that gives me this:
| user_id | active | name | user_project_id | user_id | start_date | details |
| 1 | 1 | brian | 3 | 1 | 2014-01-02 | proj 3 |
Oh please oh please let there be an answer for I will surely wither without one.
Since in MySQL there is not such things as top selectors, you can use triple JOIN, like:
SELECT
user_projects.*,
users.*
FROM
(SELECT
MAX(start_date) AS max_date,
user_id
FROM
user_projects
GROUP BY
user_id) AS max_dates
LEFT JOIN
user_projects
ON max_dates.max_date=user_projects.start_date
AND max_dates.user_id=user_projects.user_id
LEFT JOIN
users
ON users_projects.user_id=users.user_id
First select the projects per user that are the most recent:
SELECT a.*
FROM user_projects a
JOIN (
SELECT user_id, MAX(start_date) AS max_start_date
FROM user_projects
GROUP BY user_id
) b ON a.user_id = b.user_id AND a.start_date = b.max_start_date
It creates a small helper table from user_projects comprising the user and for each row their most recent project date; to get all the corresponding table fields you must join that with user_projects again.
Then, you simply join users with the above outcome to get the final result:
SELECT *
FROM users
JOIN (
SELECT a.*
FROM user_projects a
JOIN (
SELECT user_id, MAX(start_date) AS max_start_date
FROM user_projects
GROUP BY user_id
) b ON a.user_id = b.user_id AND a.start_date = b.max_start_date
) c ON users.user_id = c.user_id
select u1.user_id, u1.name, u.strat_date, u.user_project_id, u.details
from user_projects u
left outer join users u1 on u1.user_id=u.user_id
left outer join
(select user_id, max(strat_date) as strat_date user_projects group by user_id) as A
on A.user_id=u.user_id and A.strat_date=u.strat_date
You can use top 1 and order by date
select top 1 a.user_id,a.name,b.user_project_id,b.user_id,b.start_date,b.details
from users a join users_project b on a.user_id = b.user_id
order by b.start_date desc
Sorry i didnt notice mysql tag in OP's question. You can use Limit keyword.
select a.user_id,a.name,b.user_project_id,b.user_id,b.start_date,b.details
from users a join users_project b on a.user_id = b.user_id
order by b.start_date desc Limit 1
To simplify my problem: Let's say I have 3 tables.
Rooms People Things
-------- -------- --------
id| name id | name | fk_rooms id | name | fk_rooms
----------- --------------------- ---------------------
1 | kitchen 1 | John | 1 1 | TV | 2
2 | bedroom 2 | Mary | 2 2 | bed | 2
3 | Andy | 1 3 | sink | 1
4 | Laura| 1
Now I'm doing something like:
SELECT r.name AS room_name, p.name AS name, t.name AS thing FROM Rooms r
LEFT JOIN People p ON p.fk_rooms = r.id
LEFT JOIN Things t ON t.fk_rooms = r.id
which in my case works perfectly except for a few that have many to one relationship with the "Rooms" table. So instead of new rows in the result set holding the different names for "People" and "Things" in relation to the "Rooms" table, I would like to receive only two rows:
1. kitchen, John, Andy, Laura, sink
2. bedroom, Mary, TV, bed
A GROUP BY on r.id will only select one row from each table. Any help is highly appreciated!
Here it is what you're looking for:
SELECT r.name AS room_name,
GROUP_CONCAT(p.name separator ',') AS people_name,
GROUP_CONCAT(t.name separator ',') AS things
FROM Rooms r
LEFT JOIN People p ON p.fk_rooms = r.id
LEFT JOIN Things t ON t.fk_rooms = r.id
GROUP BY r.id
Yes, you need the group by clause, and you need to use the GROUP_CONCAT function. You should group your results by People.fk_rooms and Thing.fk_rooms.
Maybe you could use two different queries: The first will result the join of Rooms and People, grouped by fk_rooms, having selected three columns, they are being RoomsID, RoomName, People, while the second will result the join of Rooms and Thing, grouped by fk_rooms, having selected three columns, they are being RoomID, RoomName, Things. In your query you name these selections as t1 and t2 and join t1 and t2 by RoomsID, select t1.RoomName, t1.People, t2.Things.
Good luck.
I habe a main table that i select from and a table with subelements that i select from in a join. Example:
person skill person_to_skill
id | name id | skill id | p_id | s_id
------------ ------------ ----------------
1 | jim 1 | sewing 1 | 1 | 2
2 | peter 2 | cooking 2 | 2 | 1
3 | susan 3 | singing 3 | 2 | 3
4 | kevin 4 | 3 | 1
5 | 3 | 2
6 | 4 | 3
So now we see, sim has only one skill, peter has two and so forth.
Now if i select from person, koin skill and then also join person_to_skill, but i only want two persons. How do i manage to do so without grouping and thereby not getting all the skills?
Shortly: I want to select two persons from "person" with all their skills.
I tried just using LIMIT but that limits the result rows, not the persons.
If i use GROUP BY i only get one skill per person.
Is this possible without a subselect?
Any ideas anyone?
My Approach so far, changed to work with the example, looks like this:
SELECT p.id,p.name,s.skill
FROM person AS p
LEFT JOIN person_to_skill psk ON (psk.p_id = p.id)
LEFT JOIN skill s ON (s.id = psk.s_id)
ORDER BY p.name
LIMIT 0,2
Limit number of persons at very beginning in subquery then join to them other tables as you've already done:
SELECT p.id,p.name,s.skill
FROM (select * from person ORDER BY name LIMIT 0,2) AS p
LEFT JOIN person_to_skill psk ON (psk.p_id = p.id)
LEFT JOIN skill s ON (s.id = psk.s_id)
Added after comment:
If you really can't use subqueries you can do it using two queries. Firstly select users ids:
select id from person ORDER BY name LIMIT 0,2
and then use those ids in next query:
SELECT p.id,p.name,s.skill
FROM person p
LEFT JOIN person_to_skill psk ON (psk.p_id = p.id)
LEFT JOIN skill s ON (s.id = psk.s_id)
WHERE p.id IN (ids from previous query)
You can do something like
SELECT p.id, p.name, group_concat(s.skill separator ',')
and then group by person and limit the number of rows.