I'm trying to make something like a chart list and my actual query is like this:
SELECT
user.username,
songs.*,
albums.desc,
albums.release,
albums.name,
AVG(songrating.rating)
FROM
songs
INNER JOIN
user
ON
songs.userid=user.id
INNER JOIN
albums
ON
songs.albumid=albums.id
INNER JOIN
songrating
ON
songs.id=songrating.songid
GROUP BY
songrating.songid
it only shows entries with at least one rating entry, but I also want these without a rating
I tried to use it with if / case but it doesn't work (or I'm doing something wrong)
If I remove the avg etc, it works correctly.
It may be JOIN issue
The INNER JOIN keyword selects all rows from both tables as long as there is a match between the columns in both tables.
The LEFT JOIN keyword returns all rows from the left table (table1), with the matching rows in the right table (table2). The result is NULL in the right side when there is no match.
Try LEFT JOIN
Related
I am getting issues with the below SQL query, unable to fetch the desired result
SELECT
C.Department__c
,C.Email
,R.AcctID__c
,C.ContactID__c
,R.TransactionDueDate
,R.PubNbr__c
FROM RenewalNotificationProgramDE R
LEFT JOIN ContactNewDE C
ON R.AcctID__c = C.AcctID__c
The idea is to join all the AccountID(AcctID__c) in RenewalNotificationProgramDE table to the corresponding contacts in ContactNewDE table. AccountID is the foreign key in the ContactNewDE table. I am usig Innerjoin in my query as I want all AccountID to map with their corresponding contacts in ContactNewDE.
Just replace LEFT JOIN by INNER JOIN to get all AccountID with their corresponding contacts :-
Use below query :-
SELECT
C.Department__c
,C.Email
,R.AcctID__c
,C.ContactID__c
,R.TransactionDueDate
,R.PubNbr__c
FROM RenewalNotificationProgramDE R
INNER JOIN ContactNewDE C
ON R.AcctID__c = C.AcctID__c
You have used LEFT JOIN in your query, which you need to change it to INNER JOIN. I think you would better to notice the below notes about differences between left and inner joins:
INNER JOIN: Returns all rows when there is at least one match in BOTH
tables
LEFT JOIN: Return all rows from the left table, and the
matched rows from the right table
Im having a bit of difficulty with getting user information from one place to another.
There are 3 tables dbo.gr_usersource and dbo.gr_task and dbo.gr_user
In the dbo.gr_task table a column is filled with values that match entries in dbo.gr_usersource table that has another value that corresponds to the value in the dbo.gr_user table. You could call it a reference table between dbo.gr_task and dbo.gr_user tables.
My query looks like this;
select
dbo.gr_task.task_number
, dbo.gr_task.task_name
, dbo.gr_task.task_description
from dbo.gr_task
left join dbo.gr_user AS Handler
on dbo.gr_usersource.usersource_user = Handler.user_id
and dbo.gr_task.task_handler = dbo.gr.usersource.usersource.id
The last step would be to get the column user_name from table user when the join is working.
You have missed mediator table in your join so use as per below-
SELECT dbo.gr_task.task_number,dbo.gr_task.task_name, dbo.gr_task.task_description
FROM dbo.gr_task AS gt
LEFT JOIN dbo.gr_usersource gus ON gt.task_handler=gus.usersource.id
LEFT JOIN dbo.gr_user AS gu ON gus.usersource_user=gu.user_id;
Note: If you want only matching rows in all 3 tables then you should use normal join instead of left join.
This may work for you.
Note that there are no columns from your joined tables in your select list so left joins would have no impact on your result set.
Inner joins will filter your results set even if you bring back no columns, i.e., enforce the join condition to match rows in both tables.
SELECT
t.task_number
, t.task_name
, t.task_description
FROM dbo.gr_task t
INNER JOIN dbo.gr_usersource us
ON us.usersource.id = t.task_handler
INNER JOIN dbo.gr_user u
ON u.user_id = us.usersource_user
Having 5 tables
Table a_dates = id,
Table b_types = id, a_date_id, c_type_id,
Table c_types = id, name,
Table d_profiles = id, name, profile_type
Table e_ps = id, a_date_id, d_profile_id
From a_dates Need to get b_types,...then from b_types needs c_types name,... Then compare c_types name with d_profiles name and get d_profiles id.... if equals then create a records in e_ps with a_date_id, d_profile_id.
Could any one please help me in getting the query from inner join.
I tried like, it is incomplete query
INSERT INTO e_ps(id,a_date_id,a_date_type,d_profile_id,c_id)
SELECT '',a.id,'A',dp.id,'67' FROM d_profiles dp
INNER JOIN a_dates a ON {HERE I NEED NAME MATCHING WITH c_types name} = dp.name and dp.profile_type = 'A'
INNER JOIN a_dates ON a.id = a_dates.id
LEFT OUTER JOIN e_ps eps ON eps.a_date_type = 'A' AND eps.a_date_id = a_dates.id
WHERE eps.a_date_id IS NULL
This seems to be a relatively simple JOIN:-
INSERT INTO e_ps(id, a_date_id, d_profile_id)
SELECT NULL, a_dates.id, d_profiles.id
FROM a_dates
INNER JOIN b_types ON a_dates.id = b_types.a_date_id
INNER JOIN c_types ON b.c_type_id = c.id
INNER JOIN d_profiles ON c_types.name = d_profiles.name
With joins there are several types, and I suspect you are getting confused. Briefly:-
With an INNER JOIN it looks for a match that is on BOTH tables. If no
match the no record is returned.
With a LEFT OUTER JOIN it takes a record from the table on the left
and looks for a match on the table on the right. If a match great,
but if not then it still brings a row back but the columns from the
table on the right just have values of NULL.
A RIGHT OUTER JOIN is very much the same, just with the tables
reversed (most people including me avoid using this as it has no
advantages most of the time but just makes things confusing).
With a FULL OUTER JOIN it gets the records from both side, whether
they match or not. If they match then the columns from both are
returned, if not matched then the columns from one are returned. Not
that MySQL does not support a FULL OUTER JOIN (although there are
ways to emulate it).
A CROSS JOIN joins every combination of 2 tables. These are used when
there is no common column to match on but you want all combinations.
For example if you wanted a table of all employees and all days of
the week for each employee you would cross join a table of days of
the week against a table of employees (then for useful data you might
LEFT OUTER JOIN a table of holidays to the result).
I am trying to select data from 3 separate tables, where 2 of those contains multiple rows of data. The sql query i am using is this, but i am experiencing that when i run it, if either taskdependees or tasksdependencies have zero result, the whole task is not showing.
SELECT t.*, GROUP_CONCAT(a.DependenciesId) as DiesId, GROUP_CONCAT(b.DependeesId) as DeesId FROM tasks t JOIN tasksdependencies a ON a.TasksId=t.TasksId JOIN taskdependees b ON b.TasksId=t.TasksId GROUP BY t.TasksId
What am I doing wrong in this query?
Use LEFT JOIN , inner join will give row if there is association is present in both tables while left will return the rows from left table even if they are not associated
SELECT t.*, GROUP_CONCAT(a.DependenciesId) as DiesId,
GROUP_CONCAT(b.DependeesId) as DeesId
FROM tasks t
LEFT JOIN tasksdependencies a ON a.TasksId=t.TasksId
LEFT JOIN taskdependees b ON b.TasksId=t.TasksId
GROUP BY t.TasksId
I have to tables that I want to get all the results of both connect by a common cell. The problems is the second table only has some of records of the first table.
Table 1 forms
form_id, description, image,dept
Table 2 records
record_id, form_id, comments, added_date, done_date
If do a query like this:
SELECT * FROM form
JOIN records ON record.form_id = form.form_id
I do not get all of the forms because there is no record for that form. Is there away to do something like this? I would create a blank record for each form on in the records table, but I could not figure that out either.
This is a perfect application for a LEFT OUTER JOIN.
Example:
SELECT f.*, r.*
FROM form f
LEFT JOIN records r
ON r.form_id = f.form_id
ORDER BY f.description, r.added_date;
Use left join for these cases
SELECT * FROM form
LEFT JOIN records ON record.form_id = form.form_id
Please check which one u need --
LEFT OUTER JOIN :
Will include all records from Table Mentioned in Left Side and Matched Records from Right Side table, unmached record will be null
Ex :
SELECT *
FROM forms
LEFT JOIN records ON forms.form_id = record.form_id
FULL OUTER JOIN:
Will include all data from both table and unmatched will be null
Ex :
SELECT *
FROM forms
FULL OUTER JOIN records ON forms.form_id = record.form_id