I have 2 tables structured like this:
People
----------
>ID, Name, Surname
Projects
----------
>ID, Assistant#1, Assistant#2, Assistant#3, Assistant#4,
> Assistant#5, Assistant#6, Assistant#7, Assistant#8, Assistant#9,
> Assistant#10, lot of other columns..... (every assistant column
> contains an integer, the people ID)
Now, I want to query my DB and get a single row from Project table (let's suppose row with ID=3) containing all columns of project table and in particular have each assistant replaced with it's correct name and surname.
I've managed to do this (with a lot of joins), but with my little sql experience my code looks very bulky and i'm sure that there's a better way to do this.
Thanks in advance.
SELECT p.Name, p.Surname
FROM People p
CROSS JOIN Project j ON (p.PeopleID = j.Assistant1 OR
p.PeopleID = j.Assistant2 OR
p.PeopleID = j.Assistant3 OR
.. etc)
AND j.ProjectID = 3
Your performance will be awful, but that's the price you pay for having a horribly designed database. The better solution is to map a project and people by the means of a decomposition:
CREATE TABLE proj_people
People_ID INT
Project_ID INT
Your structure is not clear to me. I advice you to create a clutch for projects.
Tables:
Peoples
people_id, people_name, people_surname
Projects
project_id, project_name
Clutch
project_id, people_id
Because you set a number of (possible) assistants at 10, that dictates that you are going to have to write code to accomodate those 10 assistants. This can be done a few ways: (have not tested)
select * from projects proj
left join people p1 on proj.assistant1 = p1.peopleid
left join people p2 on proj.assistant2 = p2.peopleid
left join people p3 on proj.assistant3 = p3.peopleid
left join people p4 on proj.assistant4 = p4.peopleid
left join people p5 on proj.assistant5 = p5.peopleid
left join people p6 on proj.assistant6 = p6.peopleid
left join people p7 on proj.assistant7 = p7.peopleid
left join people p8 on proj.assistant8 = p8.peopleid
left join people p9 on proj.assistant9 = p9.peopleid
left join people p10 on proj.assistant10 = p10.peopleid
otherwise you could do some trickery with
select proj.projectID,
(select * from people where peopleID = proj.assistant1),
(select * from people where peopleID = proj.assistant2),
(select * from people where peopleID = proj.assistant3),
(select * from people where peopleID = proj.assistant4),
(select * from people where peopleID = proj.assistant5),
(select * from people where peopleID = proj.assistant6),
(select * from people where peopleID = proj.assistant7),
(select * from people where peopleID = proj.assistant8),
(select * from people where peopleID = proj.assistant9),
(select * from people where peopleID = proj.assistant10)
from projects proj
If possible, it might be best to re-structure your datatables, and have a single assistant mapped to a single projectID:
PeopleID, Name, Surname
ProjectID, PeopleID
Therefore, you could do just one inner join and you will return a row for each assistant:
select * from projects proj
inner join people p
on p.peopleID = proj.peopleid
where proj.projectID = PROJECTID
Your problem is that you are trying to solve a data presentation issue at the database level and this is rarely a good idea. You should have a table holding projectid and assistantid only, having the combination of both columns as the primary key of the table. This will allow you to join this table to the assistant table and the project table only once and get all the results you need. This will also have the benefit of allowing you to support many more assistants on a project in the future without having to alter your queries to add yet more joins.
In conclusion you should have 3 tables:
Project
Assistant
ProjectAssistant (projectid,assistantid)
you want to restructure your tables. I hate seeing tables with multiple columns for essentially the same thing multiple times. If you restructure to have 3 tables:
Person
PeopleID | Name | Surname
Project
ProjectID | ...other columns except Assistant
Project_Person
ProjectID | PersonID
That way you can assign multiple assistants to the same project without the need for multiple Assistant columns. Then you could use something like this to get the required results:
SELECT proj.ProjectID, pers.Name, pers.Surname
FROM Person pers
INNER JOIN Project_Person pp ON pp.PersonID = pers.PersonID
INNER JOIN Project proj ON proj.ProjectID = pp.ProjectID
This will not return a single row, but that is not how SQL is designed to work.
If you don't want to/can't change the table structure then maybe use a user defined function?
CREATE FUNCTION GET_ASS_NAME (n1 ASS_NO)
RETURNS VARCHAR(50)
DETERMINISTIC
BEGIN
DECLARE fullname VARCHAR(50);
SELECT fullname = CONCAT(NAME, ' ', SURNAME) FROM PEOPLE WHERE ID = n1;
RETURN fullname;
END|
then
select GET_ASS_NAME(1), GET_ASS_NAME(2), GET_ASS_NAME(3), ...
from PROJECTS
where ID = 3
Perhaps a cleaner design is:
People table:
People ID, Name, Surname
ProjectAssistants table:
Project ID, Assistant Person ID
Projects table:
Project ID, lots of other columns (but no Assistant columns)
Then, the SQL becomes something like:
SELECT pr.*, p.*
FROM Projects pr
JOIN ProjectAssistants p_a ON pr.ProjectID = p_a ProjectID
JOIN People p ON p_a.AssistantPersonID = p.PeopleID
WHERE ProjectID = X
Not tested :)
Select * from project pr
left join people pe1 on pe1.peopleid = pr.astint1
left join people pe2 on pe2.peopleid = pr.astint2
left join people pe3 on pe3.peopleid = pr.astint3
left join people pe4 on pe4.peopleid = pr.astint4
left join people pe5 on pe5.peopleid = pr.astint5
left join people pe6 on pe6.peopleid = pr.astint6
left join people pe7 on pe7.peopleid = pr.astint7
left join people pe8 on pe8.peopleid = pr.astint8
left join people pe9 on pe9.peopleid = pr.astint9
left join people pe10 on pe10.peopleid = pr.astint10
where pr.projectid = 3
Related
What currently happens is it just selects students from CA and students who like to skateboard. I need it to return only students who are both from CA and play soccer.
SELECT *
FROM schooldata a
INNER JOIN studentinfo b
ON b.schooldata_id = a.id
WHERE a.state = "ca"
AND ( activity = "soccer"
OR activity = "skateboard" )
You will have to do inner join based on lastname and firstname column ex:-b.lastname=a.lastname and b.firstname=a.firstname . ideally you should be maintaining primary key column of type integer in schooldata table and its foreign key reference in studentinfo and join based on those columns.
You should use join clauses. And I think base on your question. Inner Join is the best clause you should use.
SELECT column_name(s)
FROM table1
INNER JOIN table2 ON table1.column_name = table2.column_name;
I need to write a query for a scout database that compares the requirements of a badge with the skills a given member has already earned. The purpose being that several skills are applicable to multiple badges. My relevant tables (there are many) look like this:
Badge_Table:
Badge_ID,
Badge_Name,
Badge_Description,
Badge_Skills_Table:
Badge_Skill_ID,
Badge_ID,
Skill_ID,
Skills_Table:
Skill_ID,
Skill_Name,
Skill_Description,
Skills_Earned_Table:
Skills_Earned_ID
Skill_ID
User_ID
User_Table:
User_ID,
Name,
Age,
Address
Primary keys are shown in italics, and the foreign key relationships go from Badge_table to Badge_Skills_Table to Skills_Table to Skills_Earned_table to User_Table.
So far I have came up with the following ideas:
Selects all badges for named skill
SELECT badge_table.badge_name
FROM (badge_table
INNER JOIN badge_skills_table ON badge_ID
INNER JOIN Skills_Table ON skill_Id)
WHERE Skills_Table.Skill_Id = 1;
Selects all badges for each skill
SELECT badge_table.badge_name
FROM (badge_table
INNER JOIN badge_skills_table ON badge_ID
INNER JOIN Skills_Table ON skill_Id)
WHERE Skills_Table.Skill_Id = Skill_Badge_Table.Skill_Id
Selects all badges for named skill for named User - not quite working
SELECT badge_table.badge_name
FROM (badge_table
INNER JOIN badge_skills_table ON badge_ID
INNER JOIN Skills_Table ON skill_Id
INNER JOIN Skills_Earned_Table On skill_ID
INNER JOIN users_table ON user_ID)
WHERE Skills_Earned_Table.User_ID= 1 AND Skills_Earned_Table.SKILL_ID = Skill_Badge_Table.skill_ID
So can anyone help guide me with the following:
How to return all badges that a given skill is applicable for. (Done)
How to return all badges that a given scout has earned skills towards.
To return all badges the a given scout has earned all the skills for.
I'd appreciate any help you can offer,
You have no <conditions> in your ON clause. Try my query below:
SELECT A.badge_name
FROM badge_table A
INNER JOIN badge_skills_table B ON A.badge_ID=B.badge_ID
INNER JOIN Skills_Table C ON B.skill_Id=C.skill_ID
INNER JOIN Skills_Earned_Table D ON C.skill_ID=D.skill_ID
INNER JOIN users_table E ON user_ID ON D.user_ID=E.user_ID
WHERE D.User_ID= 1 AND D.skill_ID = B.skill_ID
I am trying to optimise my php by doing as much work on the MySQL server as possible. I have this sql query which is pulling data out of a leads table, but at the same time joining two tags tables to combine the result. I am looking to add a company which is linked through a relations table.
So the table that holds the relationship between the two is relations_value which simply states (I add example data)
parenttable (companies) | parentrecordid (10) | childtable (leads) | childrecordid (1)
the companies table has quite a few columns but the only two relevant are;
id (10) | companyname (my company name)
So this query currently grabs everything I need but I want to bring the companyname into the query:
SELECT leads.id,
GROUP_CONCAT(c.tag ORDER BY c.tag) AS tags,
leads.status,
leads.probability
FROM `gs_db_1002`.leads
LEFT JOIN ( SELECT *
FROM tags_module
WHERE tagid IN ( SELECT id
FROM tags
WHERE moduleid = 'leads' ) ) as b
ON leads.id = b.recordid
LEFT JOIN `gs_db_1002`.tags as c
ON b.tagid = c.id
GROUP BY leads.id,
leads.status,
leads.probability
I need to be able to go into the relations_values table and pull parenttable and parentrecordid by selecting childtable = leads and childrecordid = 1 and somehow join these so that I am able to get companyname as a column in the above query...
Is this possible?
I have created a sqlfiddle: sqlfiddle.com/#!2/023fa/2 So I am looking to add companies.companyname as column to the query.
I don't know what your primary keys and foreign keys are that link each table together.. if you could give a better understanding of what ID's are linked to eachother it would make this a lot easier... however i did something that does return the correct result... but since all of the ID's are = 1 then it could be incorrect.
SELECT
leads.id, GROUP_CONCAT(c.tag ORDER BY c.tag) AS tags,
leads.status, leads.probability, companyname
FROM leads
LEFT JOIN (
SELECT * FROM tags_module WHERE tagid IN (
SELECT id FROM tags WHERE moduleid = 'leads' )
) as b ON leads.id = b.recordid
LEFT JOIN tags as c ON b.tagid = c.id
LEFT JOIN relations_values rv on rv.id = b.recordid
LEFT JOIN companies c1 on c1.createdby = rv.parentrecordid
GROUP BY leads.id,leads.status, leads.probability
I am working on a mysql query and its giving me headache!
The Scenario:
I am building a website where people can select industries they are interested in (NOTIFY_INDUSTRY). I join the selected values and store in a database field.
Example: a member selects agriculture (id = 9) and oil and gas (id = 13). I join them as 9-13 and store in the database.
Users can select several industries, not limited to two.
Also, members can select an industry (COMPANY_INDUSTRY) it belongs in assuming Information Technology which is stored in the database too.
Sample table (members):
ID
EMAIL
COMPANY_NAME
COMPANY_INDUSTRY
NOTIFY_INDUSTRY
The problem:
When a new user registers on the website, mail (the mails are sent on daily basis) is sent to existing users who have the new user's industry (COMPANY_INDUSTRY) as one of their interested industries (NOTIFY_INDUSTRY).
What i have done:
$sql="select id, email
from members
where notify_industry in (
select company_industry
from members
where datediff($today, date_activated) <= 1)"
This does not select the right members and i do not know the right way to go about it
EDIT - Exact Problem with current output:
Does not return any row, even when it should.
Assuming the new user's company_industry is 9, and there is an existing user with notify_industry: 10-9-20; it is meant to return the existing members email as the new member is in the existing member's categories of interest; but i get blanks
As #Shiplu pointed out, this is largely a normalization issue. Despite what some people seem to think, multi-value columns are murder to try to get right.
Your basic issue is:
You have members, who are interested in one or more companies/industries, which belong to one or more industries. You table structure should probably start as:
Industry
===============
id -- autoincrement
name -- varchar
Company
==============
id -- autoincrement
name -- varchar
Company_Industry
===============
companyId -- fk reference to Company.id
industryId -- fk reference to Industry.id
Member
===============
id -- autoincrement
name -- varchar
email -- varchar
Member_Interest_Industry
=========================
memberId -- fk reference to Member.id
industryId -- fk reference to Industry.id
Member_Interest_Company
========================
memberId -- fk reference to Member.id
companyId -- fk reference to Company.id
To get all companies a member is interested in (directly, or through an industry), you can then run something like this:
SELECT a.name, a.email, c.name
FROM Member as a
JOIN Member_Interest_Company as b
ON b.memberId = a.id
JOIN Company as c
ON c.id = b.companyId
WHERE a.id = :inputParm
UNION
SELECT a.name, a.email, d.name
FROM Member as a
JOIN Member_Interest_Industry as b
ON b.memberId = a.id
JOIN Company_Industry as c
ON c.industryId = b.industryId
JOIN Company as d
ON d.id = c.companyId
WHERE a.id = :inputParm
You should redesign the tables, as others have suggested.
However, barring that, there is a gross hack you can do:
SET sql_mode = 'ANSI';
SELECT notify_members.id, notify_members.email
FROM members notify_members
INNER JOIN members new_members
WHERE CURRENT_DATE - new_members.date_activated <= 1
AND
new_members.company_industry RLIKE ('[[:<:]](' || REPLACE(notify_members.notify_industry, '-', '|') || ')[[:>:]]');
Yuck. Basically, you turn 9-13 into the MySQL regular expression [[:<:]](9|13)[[:>:]], which matches 9, 13, 13-27-61, etc., but does not match 19-131 and the like. (This supports a compound COMPANY_INDUSTRY field, too.)
Use join SQL syntax rather than a select in style..
You need to join the members table to itself.
Currently:
select id, email
from members where notify_industry in
(select company_industry
from members
where datediff($today, date_activated) <= 1
)
Use this style:
select m1.id, m1.email
from members m1
inner join members m2 on m1.company_industry = m.notify_industry
where datediff($today, m2.date_activated) <= 1
Note the use of aliasing to m1 and m2 to help understand which id and emails are returned.
This may get a little ugly but you could try the following
WARNING This will make a Cartesian Product worthy of any Mad Scientist
SELECT NotifyIndustry.id,NotifyIndustry.email
FROM
(
SELECT CONCAT('-',COMPANY_INDUSTRY,'-') company FROM members
WHERE datediff($today, date_activated) <= 1)"
) CompanyIndustry
INNER JOIN
(
SELECT CONCAT('-', NOTIFY_INDUSTRY,'-') who_to_notify
FROM members
) NotifyIndustry
ON LOCATE(company,who_to_notify)>0;
probably not the fastest query ever but this should do the job:
select m_to_notify.id, m_to_notify.email
from members m_to_notify
join members m_new_member
on '-' || m_to_notify.notify_industry || '-'
like '%-' || m_new_member.company_industry || '-%'
where datediff($today, m_new_memberdate_activated) <= 1)
I have three tables persons, jobs, jobs_persons
One person can have multiple jobs.
Person 1 is Technical Support AND Manager
Person 2 is Technical Support
Person 3 Is Manager
Job 1 Technical Support
Job 2 Manager
I need to find a query give me the result for the person who currently is Technical Support AND Manager
The answer would be only Person 1
SELECT persons.*
FROM persons INNER JOIN jobs_persons ON persons.id = jobs_persons.person_id
INNER JOIN jobs ON jobs.id = jobs_persons.job_id
WHERE job.id IN (1,2)
Returns 3 rows
SELECT persons.*
FROM persons INNER JOIN jobs_persons ON persons.id = jobs_persons.person_id
INNER JOIN jobs ON jobs.id = jobs_persons.job_id
WHERE job.id = 1 AND job.id = 2
Returns 0 rows.
I'm currently working on Ruby on Rails.
Somebody can help?
You want to use an OR operator. Using job.id = 1 AND job.id = 2 will only return elements where id equals 1 and at the same time 2. No element can do that. You want elemets where th id is 1 or where the id is 2.
to make it more obvious:
SELECT * FROM table WHERE lastname = 'Smith' AND firstname = 'James';
when executing this you obviously don't want everybody who is called Smith or James. ;-)
EDIT:
Misread the question. what you need is a second join to join the jobs table two times in and join them with the different jobs. It is a bit hard as you didn't show the schema, but this might work:
SELECT persons.*
FROM persons
INNER JOIN jobs_persons jp1 ON persons.id = jp1.person_id
INNER JOIN jobs_persons jp2 ON persons.id = jp2.person_id
INNER JOIN jobs j1 ON j1.id = jp1.job_id
INNER JOIN jobs j2 ON j2.id = jp2.job_id
WHERE j1.id = 1 AND j2.id = 2
Try this to get all the person who has got a job of 1 AND 2 in your associative entity table. No need to hit the job table.
SELECT p.*
FROM persons p
WHERE id in (
SELECT person_id FROM jobs_persons
WHERE job_id IN (1,2)
GROUP BY person_id
HAVING COUNT(*) = 2
);
With your recent comments, it seems you're having performance problems. That's really outside of the scope of this question and answer.
You need to make sure your indexes are in place on the appropriate columns:
jobs_person.job_id
persons.id