better way of doing this SELECT in MySQL - mysql

Best way to do this SELECT?
I've got this tables:
t_department
id
name
t_users
id
name
type
*type can be:
1 SuperUser
2 normalUser
t_department_superuser
(A department can have many superUsers)
-idSuperUser
-idDepartment
t_superuser_normaluser
(A superUser can have many normalusers)
-idSuperUser
-idNormalUser
and finally
t_actions
-id (autonumeric)
-idUser (this can be an id of superUser or normalUser)
-action
Given a department name, for example "mainDepartment"
I need to get all records from t_actions of all normalusers and all superusers of that department
I have this, it works, but I am not an SQL expert (I am using MySQL) and I think it is not the best way to do the select, and t_actions is going to have loads of rows:
SELECT id,idUser,action
FROM t_actions
WHERE (idUser IN (
SELECT DISTINCT t_department_superuser.idSuperUser FROM t_department
RIGHT JOIN t_department_superuser ON t_department_superuser.idDepartment = t_department.id
LEFT JOIN t_superuser_normaluser ON t_superuser_normaluser.idSuperUser = t_department_superuser.idSuperUser
WHERE name='mainDepartment'
UNION ALL
SELECT DISTINCT t_superuser_normaluser.idNormalUser
FROM t_department
RIGHT JOIN t_department_superuser ON t_department_superuser.idDepartment = t_department.id
LEFT JOIN t_superuser_normaluser ON t_superuser_normaluser.idSuperUser = t_department_superuser.idSuperUser
WHERE name='mainDepartment')
ORDER BY id;
Any suggestions to make this better? thank you!!

because you are using left and right joins there will be null records, which is why you need the UNION... you can cut out the UNION with a simple null check
SELECT id, idUser, action
FROM t_actions
WHERE idUser IN
( SELECT DISTINCT COALESCE(tsn.idNormalUser, tds.idSuperUser)
FROM t_department td
RIGHT JOIN t_department_superuser tds ON tds.idDepartment = td.id
LEFT JOIN t_superuser_normaluser tsn ON tsn.idSuperUser = tds.idSuperUser
WHERE td.name='mainDepartment'
)
ORDER BY id;
note i also added alias's to your table names so its easer to write out and read the columns you are trying to select and join on.
EDIT
with the data the only possible way to do it with this table design is like this
SELECT id, idUser, action
FROM t_actions
WHERE idUser IN
((SELECT tds.idSuperUser
FROM t_department td
JOIN t_department_superusers tds ON tds.idDepartment = td.id
WHERE td.name='MAIN')
UNION
(SELECT tsn.idNormalUser
FROM t_department td
JOIN t_department_superusers tds ON tds.idDepartment = td.id
JOIN t_superuser_normaluser tsn ON tsn.idSuperUser = tds.idSuperUser
WHERE td.name='MAIN')
)
ORDER BY id;

Related

How to make query

review table has store_idx, user_idx etc...
I want to create a query sentence that gets information about the store to which the user has bookmarked with the user_id value entered.
The query sentence I made is
select A.store_name
, A.store_img
, count(B.store_idx) as review_cnt
from board.store A
Left
Join board.review B
On A.store_idx is B.store_idx
where store_idx is (select A.store_idx from bookmark where user_id = ?)
However, nothing came out as a result.
Help me..
Please use below Query:
SELECT store_name
, store_img
, SUM(review_cnt) AS review_cnt
FROM
( SELECT DISTINCT A.store_name
, A.store_img
, CASE WHEN B.store_idx IS NULL THEN 0 ELSE 1 END AS review_cnt
FROM bookmark br
JOIN board.store A
ON A.store_idx = br.store_idx
LEFT
JOIN board.review B
ON A.store_idx = B.store_idx
WHERE br.user_id = ?
)T
The WHERE clause is obviously filtering out all rows. We can't do much about that. But your query is also lacking a GROUP BY, the table aliases can be improved, and the join condition is not correct.
So, try this version:
select s.store_name, s.store_img, count(b.store_idx) as review_cnt
from board.store s left join
board.review r
on s.store_idx = r.store_idx
where b.store_idx in (select b.store_idx
from bookmark b
where b.user_id = ?
);

INTERSECT query in MariaDB

I have a problem with this query in MariaDB language. I want to do an intersect with the same field but with two values. The problem is that i can't use the INTERSECT query.
How can I do it?? I have tried with exists and inner join but it still doesn't work.
SELECT nombre
FROM actores
WHERE codactor IN ( SELECT actor
FROM participacion
WHERE (titulo,año) IN (SELECT titulo, año
FROM peliculas
WHERE director IN (
SELECT coddirector
FROM directores d
WHERE d.nombre='Alejandro'
AND d.apellido='Amenabar')))
INTERSECT
SELECT nombre
FROM actores
WHERE codactor IN ( SELECT actor
FROM participacion
WHERE (titulo,año) IN (SELECT titulo,año
FROM peliculas
WHERE director in (
SELECT coddirector
from directores p
WHERE p.nombre='Pedro'
AND p.apellido='Almodobar')));
INTERSECT was introduced in MariaDB 10.3.0.
INTERSECT
The result of an intersect is the intersection of right and left SELECT results, i.e. only records that are present in both result sets will be included in the result of the operation.
(SELECT e_name AS name, email FROM employees)
INTERSECT
(SELECT c_name AS name, email FROM customers);
As for your query you could leave it as is.
First try it like this, to check you have all the actors. I have to add codactor in case you have actors with same name.
SELECT a.codactor, a.nombre -- add ', *' to see all columns and test query is ok.
FROM actores a
JOIN participacion p
ON a.codactor = p.actor
JOIN peliculas m
ON p.titulo = m.titulo
AND p.ano = m.ano
JOIN directores d
ON p.director = d.coddirector
WHERE (d.nombre = 'Alejandro' and d.apellido = 'Amenabar')
OR (d.nombre = 'Pedro' and d.apellido = 'Almodobar')
Then add GROUP BY to see which actor are in movies from both directors.
GROUP BY a.codactor, a.nombre
HAVING COUNT(DISTINCT coddirector) = 2

SQL select rows that have one value but not another

I have a table in SQL which will contain multiple rows for one id, as below
accountid Productname
1 GL
1 IP
1 MI
2 GL
2 IP
2 PA
3 MI
3 CP
3 IP
4 GL
4 CP
4 CI
I want to be able to select all accounts which have certain products but not other. For example all that have IP or GL but not MI, using the sample table above this would return accounts 2 and 4.
SELECT ccx_accountidname
FROM (
SELECT ccx_accountidname, ccx_productname
FROM Filteredccx_leadresearch
WHERE ccx_productname IN ('GL','IP')
AND ccx_accountidname IS NOT NULL
) AS T
WHERE ccx_productname NOT IN ('MI')
ORDER BY ccx_accountidname
and
SELECT DISTINCT LR1.ccx_accountidname
FROM Filteredccx_leadresearch LR1
LEFT JOIN Filteredccx_leadresearch LR2 ON LR1.ccx_accountid = LR2.ccx_accountid
AND LR2.ccx_productname IN ('GL', 'IP')
WHERE LR1.ccx_productname NOT IN ('MI')
AND LR1.ccx_accountidname IS NOT NULL
ORDER BY LR1.ccx_accountidname
Both give basically the same results, is there any way this can be done?
Thanks in advance for any help
Could you try this:
SELECT DISTINCT T1.Accountidname FROM TheTableThatContainsAccountnames as T1
JOIN AccountProductsTable as T2 on T1.AccountId=T2.AccountId
WHERE T2.ProductName = 'ProductYouWant'
AND T2.ProductName = 'AnOtherProductYouWant'
According to your post, all you really need is a simple query with the correct and logic. You want all accounts with Product name GL or IP but not in MI. This will do it without any other joins.
SELECT ccx_accountidname
FROM Filteredccx_leadresearch
WHERE
ccx_productname in ('GL','IP')
and ccx_productname not in ('MI')
EDIT
This will get you the account, though I doubt it will work in your overall solution. It's just hard to tell without seeing your complete dataset. This could be done with parameters too.
IF OBJECT_ID('tempdb..#TempTable') IS NOT NULL
DROP TABLE #TempTable
IF OBJECT_ID('tempdb..#TempTableTwo') IS NOT NULL
DROP TABLE #TempTableTwo
create table #TempTable (accountid int, productname char(2))
insert into #TempTable (accountid,productname) values
(1,'GL'),
(1,'IP'),
(1,'MI'),
(2,'GL'),
(2,'IP'),
(2,'MA')
select distinct
t1.accountid,
1 as T
into #TempTableTwo
from
#TempTable t1
where
productname in ('GL','IP')
union all
select distinct
t1.accountid,
-1 as T
from
#TempTable t1
where
productname in ('MI')
select
accountid
from #TempTableTwo
group by accountid
having sum(T) > 0
I might be late for the game, but this should do the trick, if anyone is trying to solve a similar problem. I renamed your table and it's columns:
Filteredccx_leadresearch -> l_search
ccx_accountidname -> a_name
ccx_productname -> p_name
And here's the SQL:
(SELECT DISTINCT t1.a_name
FROM l_search t1
JOIN l_search t2 ON t1.a_name = t2.a_name
WHERE t1.p_name = 'IP'
OR t2.p_name = 'GL')
MINUS
(SELECT DISTINCT t1.a_name
FROM l_search t1
JOIN l_search t2 ON t1.a_name = t2.a_name
WHERE ((t1.p_name = 'IP'OR t1.p_name = 'GL') AND t2.p_name = 'MI')
OR
(t1.p_name = 'MI' AND (t1.p_name = 'IP' OR t1.p_name = 'GL')));
First set:
cross product of table on itself with same IDs, get account IDs which have a product 'IP' or 'GL'.
Second set:
cross product of table on itself with same IDs, get account IDs which have p_name ('IP' OR 'GL') on first cross property AND 'MI' on second.
Also, get those IDs, which have the same but the other way around: p_name 'MI' on first cross property AND ('IP' OR 'GL') on second.
And finally subtract the second from the first.
Here is a simple way to include the accounts that match either IP or GL and exclude those accounts if they have an record for MI without using a subquery.
This is assuming t1 is a table that has unique account numbers in accountid and t2 is the table you have shown above that has accountid and Productname columns.
SELECT DISTINCT
t1.accountid
FROM t1
LEFT JOIN t2 AS t2_match
ON t1.accountid = t2_match.accountid
AND
(
t2_match.Productname = 'IP'
OR t2_match.Productname = 'GL'
)
LEFT JOIN t2 AS t2_not_match
ON t1.accountid = t2_not_match.accountid
AND t2_not_match.Productname = 'MI'
WHERE
t2_match.accountid IS NOT NULL
AND t2_not_match.accountid IS NULL
This is really late, but it might help some one.
I'll focus only on using the columns we have on the table we are shown (won't combine it with other tables we were not given).
Since the only table in the example is not clearly named, I'll call it some_table
SELECT t.accountidname, t.productname
FROM some_table t
WHERE t.productname IN ('GL','IP')
AND t.accountidname NOT IN (
SELECT accountidname
FROM some_table
WHERE productname = 'MI'
);
The idea here is to:
Select all accountid and productname that have productname either GL or IP (3rd line)
Select all accountid that have a productname MI and remove them from the values we already have (4th line onwards)
With this values, filtering or combining it with other tables should be rather trivial.
You might want to replace the SELECT with SELECT DISTINCT if the combinations of accountid and productname could be repeated in the table.

Full outer join in mysql with movie database

Hi I have the following tables and columns.
movie: ID, title
person: ID, name
involved: personID, movieID
I need to answer the question:
"Which movies have either John Travolta or Uma Thurman, but not both starred in?"
I couldn't figure out how to do this without creating new tables, so I made 2 new tables. And tried to do the full outer join on, where you dont get intersecting results. I found out that you can't do full outer joins in mysql but had to do a left join, unioned with a right join. I tried this but don't get the results I wanted at all. I have been stuck for a while now. Can anyone point me in the right direction?
This is what I have so far.
DROP TABLE IF EXISTS Umatable;
DROP TABLE IF EXISTS Johntable;
CREATE TABLE Umatable(title VARCHAR(500));
CREATE TABLE Johntable(title VARCHAR(500));
INSERT INTO Umatable
SELECT m.title
FROM movie m, person p, involved i
WHERE p.name = "Uma Thurman"
AND p.id = i.personid
AND m.id = i.movieiD;
INSERT INTO Johntable
SELECT m.title
FROM movie m, person p, involved i
WHERE p.name = "John Travolta"
AND p.id = i.personid
AND m.id = i.movieiD;
SELECT *
FROM Umatable
LEFT JOIN Johntable ON Umatable.title = Johntable.title
WHERE Johntable.title IS NULL OR Umatable.title IS NULL
UNION
SELECT *
FROM Umatable
RIGHT JOIN Johntable ON Umatable.title = Johntable.title
WHERE Johntable.title IS NULL OR Umatable.title IS NULL
I would do this using aggregation and having:
select i.movieId
from involved i join
person p
on p.id = i.personId
group by i.movieId
having sum(p.name in ('John Travolta', 'Uma Thurman')) = 1;
A count(*) inside a correlated subquery will work:
select *
from movie m
where 1 = (select count(*)
from involved i
join person p
on p.ID = i.personID
and p.name IN ('John Travolta', 'Uma Thurman')
where i.movieID = m.ID)
SQLFiddle Demo

MySQL SELECT DISTINCT ORDER BY problem

To begin with I have 4 tables I am dealing with.
I have a classes table that is a 1->N relationship with a sections table which also has a 1->N relationship with a lessons table.
So to put it in perpective:
Classes
Sections
Lessons
The last table is an activityLog, when the student accesses a lesson this is recorded using the following:
ActivityLog Row -> actorID (user ID), classID, sectionID, lessonID
I want to pull out the last 5 unique lessons the student has visited. I tried using both DISTINCT and GROUP BY without success.
The same records are being returned each time, not the latest classes that they have visited.
Using GROUP BY
SELECT activityLog.actorID, activityLog.activityDate,
strClasses.classID, strClasses.className,
strSections.sectionID, strSections.sectionName,
strLessons.lessonID, strLessons.lessonName
FROM activityLog
LEFT JOIN strClasses ON strClasses.classID = activityLog.classID
LEFT JOIN strSections ON strSections.sectionID = activityLog.sectionID
LEFT JOIN strLessons ON strLessons.lessonID = activityLog.lessonID
WHERE activityLog.activityTypeID = 6 AND activityLog.actorID = 3
GROUP BY activityLog.lessonID
ORDER BY activityLog.activityDate DESC
LIMIT 5
Using DISTINCT
SELECT DISTINCT activityLog.actorID,
strClasses.classID, strClasses.className,
strSections.sectionID, strSections.sectionName,
strLessons.lessonID, strLessons.lessonName
FROM activityLog
LEFT JOIN strClasses ON strClasses.classID = activityLog.classID
LEFT JOIN strSections ON strSections.sectionID = activityLog.sectionID
LEFT JOIN strLessons ON strLessons.lessonID = activityLog.lessonID
WHERE activityLog.activityTypeID = 6 AND activityLog.actorID = 3
ORDER BY activityLog.activityDate DESC
LIMIT 5
I cannot figure out why the latest records are not being displayed.
Based on your change, how does this suit you?
SELECT activityLog.actorID, activityLog.activityDate,
strClasses.classID, strClasses.className,
strSections.sectionID, strSections.sectionName,
strLessons.lessonID, strLessons.lessonName
FROM activityLog
LEFT JOIN strClasses ON strClasses.classID = activityLog.classID
LEFT JOIN strSections ON strSections.sectionID = activityLog.sectionID
LEFT JOIN strLessons ON strLessons.lessonID = activityLog.lessonID
WHERE activityLog.activityTypeID = 6 AND activityLog.actorID = 3
AND activityLog.activityDate = (SELECT MAX(activityDate) FROM activityLog AS lookup WHERE lessonID = activityLog.lessonID)
ORDER BY activityLog.activityDate DESC
LIMIT 5
Based on your description, I'm not sure why you're using LEFT JOIN, but I've left it in just in case.
Try group by like below
GROUP BY activityLog.classID,activityLog.sectionID,activityLog.lessonID
I think it will work, or just sent me create scripts for these I will create that query
Well, there's got to be a datetime in the ActivityLog I hope... so Try this:
Select s.Name, c.ClassName
From Students s
left Join On Classes c
On c.ClassId In
(Select Distinct ClassId From Classes
Where (Select Count(Distinct ClassId) From Classes ic
Join ActivityLog l On l.UserId = s.UserId
And l.ClassId = c.ClassId
Where classId = c.ClassId
And activityDateTime > l.activityDateTime)
< 5)