I have 2 tables as shown below and I want to search users who have vehicle "motorbike" AND "car", related to the tables, the search result should show only (1) john , not (3) mark, because I want "AND" not "OR".
How is it done with MySQL query ?
select * from members m left join properties p on m.user_id = p.user_id where concat_ws(',',property,value) in ('vehicle,motorbike','vehicle,car')
try this:
select name from members m, properties p where m.user_id=p.user_id and p.value="moterbike" and p.value="car";
Use the HAVING clause:
SELECT
A.user_id,
name,
property
FROM members A
INNER JOIN properties B
ON A.user_id=B.user_id
WHERE value IN ('motorbike','car')
GROUP BY A.user_id,name,property
HAVING COUNT(A.user_id)<>1
with respect,
I think some time it gives wrong result if we use having example because some time value can have 2 or more cars in same user
join example not retrieving any record
my answer is this
SELECT cc.*,mem.name
FROM
(SELECT user_id
FROM propoties
WHERE value='car') cc
JOIN
(SELECT userid
FROM properties
WHERE value='moterbyke') mb ON cc.userid=mb.userid
JOIN member mem ON cc.memberid=mem.memberid
Related
So I have the below database structure
TABLES ------- Columns
person: id, name, salary, address
group: id, name
person_group: person_id, groud_id
So here is my query which is used to get all persons along with the groups they are associated with
SELECT p.id, p.name,
group_concat(g.name) as groups
FROM person_group pg, group g, person p
WHERE pg.group_id = g.id AND pg.novel_id = n.id
GROUP BY ng.person_id
So this query gives me data like
id name groups
2345 John Admin, SuperAdmin, RedHat
But the problem is: if that person doesn't belong to any group, the query doesn't return that person!
Any would be appreciated!
Never use commas in the FROM clause. Always use proper, explicit JOIN syntax.
That is exactly your problem here. When you are writing more than one table in the FROM clause, you should be thinking "what type of JOIN do I need". If you had that thought, you would immediate realize that you need an outer join to do what you want:
SELECT p.id, p.name, group_concat(g.name) as groups
FROM person p LEFT JOIN
person_group pg
ON pg.person_id = p.id LEFT JOIN
group g
ON pg.group_id = g.id
GROUP BY p.id, p.name;
If you don't know what an outer join is, then that is all the more reason to use the proper, explicit syntax, so you can learn.
I have two tables (user and I_S) and the I_S table contains a column called score. I need to obtain the highest score and the corresponding user name from the tables.
I used a left join but I keep getting an error saying
Unknown column 'I_S.total_score' in 'field list'
This is the query I used.
SELECT MAX(interview_sessions.total_score)
FROM interview_sessions as sc
LEFT JOIN user as u on sc.user_id = u.user_id
SELECT DISTINCT users.name, I_S.score FROM users
LEFT JOIN I_S ON I_S.user_id = users.user_id WHERE score IN (SELECT MAX(score) FROM I_S)
All users with Max score.
And i think you should write sc.total_score instead interview_sessions.total_score in your query because you use alias
Try using this:
SELECT MAX(sc.total_score)
FROM interview_sessions as sc
LEFT JOIN user as u on sc.user_id = u.user_id
You need an inner query to first determine WHAT is the highest score. Form that, re-join to the interview sessions table on THAT max score. Then join to users to get the names. It is possible multiple people can have a same max score.
select
from
( SELECT MAX(i_s.total_score) as MaxScore
from interview_sessions i_s ) maxAll
JOIN interview_sessions i_s2
on maxAll.MaxScore = i_s2.total_score
JOIN User u
on i_s2.user_id = u.user_id
try this way
select b.*,a.totalscore from user b
inner join( select userid,max(total_score) as totalscore from I_S) a on a.userid=b.userid
It works but what I would like is to list username, first name, last name not all but I've tried JOIN and isn't seeming to work. Any ideas? Thanks!
MY DB:
http://gyazo.com/eb13cd68440d20719ce0783018cb9828
SELECT
M.Username,
M.first_name,
M.Last_name,
COUNT(1) AS num_comments
FROM members AS M
INNER JOIN comments AS C
ON C.memberID = M.memberID
GROUP BY
C.memberID
ORDER BY COUNT(1) DESC
LIMIT 1
This matches the Member to all their comments, groups by the member to get the count of comments for the users, orders by the count starting highest first, then returns the first result.
Instead of selecting * (ALL) just use SELECT table.username, table.firstname, table.lastname [...].
You can leave out the table. if all information is stored in your comments table. If not, adjust accordingly. In that case you'll also need to Join the comments table with the table where the rest of the information is stored.
Edit:
SELECT m.username, m.first_name, m.last_name FROM members m, comments c WHERE m.MemberID = c.MemberID AND c.author = (select max(author) from comments)
I m working in MySQL and have to write a select query.
I have related data in four tables. Now, the parent table may have data whose child data may not be present in lower tables.
I want to write a single query to get data from all four tables, irrespective of situation that data is present in child tables or not.
I have tried to write nested select and joins as below, but m not getting the data.
select * from property p where p.Re_ID in
(select Re_id from entry e where e.Re_ID in
(select Re_id from category c where c.Re_ID in
(select id from re)))
Please help me how to get data from all 4 tables.
If cir_registry is the master, you can select from that and LEFT JOIN the other tables in the order they're distant from cir_registry;
SELECT r.ID rId, r.Description rDescription, c.ID cId ...
...
p.Data_Type pDataType
FROM cir_registry r
LEFT JOIN cir_category c ON c.Registry_ID = r.ID
LEFT JOIN cir_entry e ON e.Category_ID = c.ID
LEFT JOIN cir_property p ON p.Entry_IDInSource = e.IDInSource
You should also alias the columns as above, otherwise, for example, p.ID and c.ID will both show up in the result set as ID, and you'll only be able to access one of them.
You might need UNION? Something like:
Select * FROM cir_registry
Union
Select * FROM cir_entry
Union
Select * FROM cir_property
Check the official doc here: http://dev.mysql.com/doc/refman/5.0/en/union.html
I have a left join to a table and want to count columns from it, after grouping by a column of the parent table:
SELECT * , COUNT(list.id) AS listcount, COUNT(uploads.id) AS uploadcount
FROM members
LEFT JOIN lists ON members.id= list.mid
LEFT JOIN uploads ON members.id= uploads.mid
GROUP BY members.id
Assume that a user can have either lists or uploads based on the type of user. Then is above query good enough? If not why?
Or do I have to use this query?
SELECT * , l.listcount, u.uploadcount
FROM members
LEFT JOIN (select count(lists.id) as listscount,mid from lists group by mid) as l
on l.mid = m.id
LEFT JOIN (select count(uploads.id) as uploadscount
,mid from uploads group by mid) as u on u.mid = m.id
GROUP BY members.id
Or correlated subqueries?
SELECT *,
(select count(lists.id) as listscount from lists as l where l.mid = m.id
group by mid) as listcount
(select count(uploads.id) from uploads as u where u.mid = m.id
group by mid) as uploadscount
FROM members
GROUP BY members.id
And which is best solution?
The alias m for members is missing in query 2 and 3. Otherwise they should give the same numbers.
Query 2 (fixed) will perform fastest.
Query 1 is different in that it will give a higher number for uploads, if there are cases of multiple lists per member. After joining to lists, there will be multiple rows for a member too, which will increase the count for uploads. So query 1 is probably wrong.
Also, NULL values are not counted. The manual informs:
COUNT(expr)
Returns a count of the number of non-NULL values of expr in the rows
retrieved by a SELECT statement. The result is a BIGINT value.