I am trying to write a query. I got it work half way, but I am having problems with the LEFT JOIN.
I have three tables:
user
user_preferences
user_subscription_plan
User will always have one user_preference, but it can have many or no entries in the user_subscription_plan
If the user has no entry in the user_subscription_plan, or if he has only one then my sql works. If I have more then one, then I have issue. In the case of two entries, how can I make it to return the last one entered? I tried playing with ORDER statement, but it does not work as expected. Somehow I get empty rows.
Here is my query:
SELECT u.id AS GYM_USER_ID, subscription_plan.id AS subscriptionId, up.onboarding_completed AS CompletedOnboarding,
(CASE
WHEN ((up.onboarding_completed = 1)
AND (ISNULL(subscription_plan.id)))
THEN 'freemiun'
WHEN (ISNULL(up.onboarding_completed)
AND (ISNULL(subscription_plan.id)))
THEN 'not_paying'
END) AS subscription_status
FROM user AS u
INNER JOIN user_preferences up ON up.user_id = u.id
LEFT JOIN (
SELECT * FROM user_subscription_plan AS usp ORDER BY usp.id DESC LIMIT 1
) AS subscription_plan ON subscription_plan.user_id = u.id
GROUP BY u.id;
If I run it as it is, then subscription_plan.id AS subscriptionId is always empty.
If I remove the LIMIT clause, then its not empty, but I am still getting the first entry, which is wrong in my case
I have more CASE's to cover, but I can't process until I solve this problem.
Please try to use "max(usp.id)" that "group by subscription_plan.user_id" instead of limit 1.
If you limit 1 in the subquery, the subquery's result will always return only 1 record (if the table has data).
So the above query can be rewritten like this.
Sorry, I didn't test, because I don't have data, but please try, hope this can help.
SELECT
u.id AS GYM_USER_ID,
subscription_plan.id AS subscriptionId,
up.onboarding_completed AS CompletedOnboarding,
(CASE
WHEN
((up.onboarding_completed = 1)
AND (ISNULL(subscription_plan.id)))
THEN
'freemiun'
WHEN
(ISNULL(up.onboarding_completed)
AND (ISNULL(subscription_plan.id)))
THEN
'not_paying'
END) AS subscription_status
FROM
user AS u
INNER JOIN
user_preferences up ON up.user_id = u.id
LEFT JOIN
(SELECT
usp.user_id, MAX(usp.id)AS id
FROM
user_subscription_plan AS usp
GROUP BY usp.user_id) AS subscription_plan ON subscription_plan.user_id = u.id;
Related
I want to get all the data from the users table & the last record associated with him from my connection_history table , it's working only when i don't add at the end of my query
ORDER BY contributions DESC
( When i add it , i have only the record wich come from users and not the last connection_history record)
My question is : how i can get the entires data ordered by contributions DESC
SELECT * FROM users LEFT JOIN connections_history ch ON users.id = ch.guid
AND EXISTS (SELECT 1
FROM connections_history ch1
WHERE ch.guid = ch1.guid
HAVING Max(ch1.date) = ch.date)
The order by should not affect the results that are returned. It only changes the ordering. You are probably getting what you want, just in an unexpected order. For instance, your query interface might be returning a fixed number of rows. Changing the order of the rows could make it look like the result set is different.
I will say that I find = to be more intuitive than EXISTS for this purpose:
SELECT *
FROM users u LEFT JOIN
connections_history ch
ON u.id = ch.guid AND
ch.date = (SELECT Max(ch1.date)
FROM connections_history ch1
WHERE ch.guid = ch1.guid
)
ORDER BY contributions DESC;
The reason is that the = is directly in the ON clause, so it is clear what the relationship between the tables is.
For your casual consideration, a different formatting of the original code. Note in particular the indented AND suggests the clause is part of the LEFT JOIN, which it is.
SELECT * FROM users
LEFT JOIN connections_history ch ON
users.id = ch.guid
AND EXISTS (SELECT 1
FROM connections_history ch1
WHERE ch.guid = ch1.guid
HAVING Max(ch1.date) = ch.date
)
We can use nested queries to first check for max_date for a given user and pass the list of guid to the nested query assuming all the users has at least one record in the connection history table otherwise you could use Left Join instead.
select B.*,X.* from users B JOIN (
select A.* from connection_history A
where A.guid = B.guid and A.date = (
select max(date) from connection_history where guid = B.guid) )X on
X.guid = B.guid
order by B.contributions DESC;
Below is an sql query that im using to get a list of users who doest have contact details added. The below query seems to work fine. But the only problem is that the image value always returns NULL
I tried to use a sub query to image the image link.Everything works except for the image link.
SELECT a.id,a.name,a.address,a.image_id,(select url
from meta_details b
where b.p_id = 'a.image_id'
and b.meta_val='profile_pic') as image
FROM users
WHERE a.user_id NOT IN (SELECT user_id FROM details where contact_id != '$cid')
Im not sure if this is the correct way, is it possible to make it work to get the image url?
You should remove the quote around a.image_id ( otherwise instead of a join condition on field you have a join on literal value 'a.image_id' that fails because don't match )
SELECT
a.id
,a.name
,a.address
,a.image_id
,(select url
from meta_details b
where b.p_id = a.image_id and b.meta_val='profile_pic' ) as image
FROM users a
WHERE a.user_id NOT IN (SELECT user_id FROM details where contact_id != '$cid')
This type of query can also be expressed with join operations:
select u.*, md.url as image
from users u left join
meta_details md
on md.p_id = u.image_id and
md.meta_val = 'profile_pic' left join
details d
on d.user_id = u.user_id and d.contact_id <> '$cid'
where d.user_id is null;
The advantage to this approach is that the SQL optimizer has a chance of producing a better optimization plan. Also, NOT IN is dangerous because if any rows from the subquery return NULL, then no rows at all will be returned from the query.
While working on a system I'm creating, I attempted to use the following query in my project:
SELECT
topics.id,
topics.name,
topics.post_count,
topics.view_count,
COUNT( posts.solved_post ) AS solved_post,
(SELECT users.username AS posted_by,
users.id AS posted_by_id
FROM users
WHERE users.id = posts.posted_by)
FROM topics
LEFT OUTER JOIN posts ON posts.topic_id = topics.id
WHERE topics.cat_id = :cat
GROUP BY topics.id
":cat" is bound by my PHP code as I'm using PDO. 2 is a valid value for ":cat".
That query though gives me an error: "#1241 - Operand should contain 1 column(s)"
What stumps me is that I would think that this query would work no problem. Selecting columns, then selecting two more from another table, and continuing on from there. I just can't figure out what the problem is.
Is there a simple fix to this, or another way to write my query?
Your subquery is selecting two columns, while you are using it to project one column (as part of the outer SELECT clause). You can only select one column from such a query in this context.
Consider joining to the users table instead; this will give you more flexibility when selecting what columns you want from users.
SELECT
topics.id,
topics.name,
topics.post_count,
topics.view_count,
COUNT( posts.solved_post ) AS solved_post,
users.username AS posted_by,
users.id AS posted_by_id
FROM topics
LEFT OUTER JOIN posts ON posts.topic_id = topics.id
LEFT OUTER JOIN users ON users.id = posts.posted_by
WHERE topics.cat_id = :cat
GROUP BY topics.id
In my case, the problem was that I sorrounded my columns selection with parenthesis by mistake:
SELECT (p.column1, p.column2, p.column3) FROM table1 p WHERE p.column1 = 1;
And has to be:
SELECT p.column1, p.column2, p.column3 FROM table1 p WHERE p.column1 = 1;
Sounds silly, but it was causing this error and it took some time to figure it out.
This error can also occur if you accidentally use commas instead of AND in the ON clause of a JOIN:
JOIN joined_table ON (joined_table.column = table.column, joined_table.column2 = table.column2)
^
should be AND, not a comma
This error can also occur if you accidentally use = instead of IN in the WHERE clause:
FOR EXAMPLE:
WHERE product_id = (1,2,3);
COUNT( posts.solved_post ) AS solved_post,
(SELECT users.username AS posted_by,
users.id AS posted_by_id
FROM users
WHERE users.id = posts.posted_by)
Well, you can’t get multiple columns from one subquery like that. Luckily, the second column is already posts.posted_by! So:
SELECT
topics.id,
topics.name,
topics.post_count,
topics.view_count,
posts.posted_by
COUNT( posts.solved_post ) AS solved_post,
(SELECT users.username AS posted_by_username
FROM users
WHERE users.id = posts.posted_by)
...
I got this error while executing a MySQL script in an Intellij console, because of adding brackets in the wrong place:
WRONG:
SELECT user.id
FROM user
WHERE id IN (:ids); # Do not put brackets around list argument
RIGHT:
SELECT user.id
FROM user
WHERE id IN :ids; # No brackets is correct
This error can also occur if you accidentally miss if function name.
for example:
set v_filter_value = 100;
select
f_id,
f_sale_value
from
t_seller
where
f_id = 5
and (v_filter_value <> 0, f_sale_value = v_filter_value, true);
Got this problem when I missed putting if in the if function!
Another place this error can happen in is assigning a value that has a comma outside of a string. For example:
SET totalvalue = (IFNULL(i.subtotal,0) + IFNULL(i.tax,0),0)
(SELECT users.username AS posted_by,
users.id AS posted_by_id
FROM users
WHERE users.id = posts.posted_by)
Here you using sub-query but this sub-query must return only one column.
Separate it otherwise it will shows error.
I also have the same issue in making a company database.
this is the code
SELECT FNAME,DNO FROM EMP
WHERE SALARY IN (SELECT MAX(SALARY), DNO
FROM EMP GROUP BY DNO);
I cannot figure out why this is not working. Basically, I am running a subquery to count all rows of p.songid WHERE trackDeleted=0. The subquery works fine when I execute it by itself, but when I implement I get "subquery returned more than 1 row".
SELECT u.username, u.id, u.score, s.genre, s.songid, s.songTitle, s.timeSubmitted, s.userid, s.insWanted, s.bounty,
(SELECT COUNT(p.songid)
FROM songs s
LEFT JOIN users u
ON u.id = s.userid
LEFT JOIN posttracks p
ON s.songid = p.songid
WHERE p.trackDeleted=0
GROUP BY s.timeSubmitted ASC
LIMIT 25)
AS trackCount
FROM songs s
LEFT JOIN users u
ON u.id = s.userid
LEFT JOIN posttracks p
ON s.songid = p.songid
WHERE paid=1 AND s.timeSubmitted >= ( CURDATE() - INTERVAL 60 DAY )
GROUP BY s.timeSubmitted ASC
LIMIT 25
Obviously, a sub-query can't return more than one row, as this makes no sense. You only expect one value to be returned - COUNT(p.songid) - yet you GROUP BY s.timeSubmitted, which will make it return multiple rows, and multiple counts of p.songid.
Think about it this way, a subquery in the SELECT statement like you have needs to return a single value since it is going to act like just another column in your select list. Since you have a LIMIT 25 on yours, you're obviously expecting more than one value back, which is inocrrect for this usage.
OK, your query is a mess. Not only is the subquery broken, but I'm pretty sure the GROUP BY s.timeSubmitted ASC isn't doing what you think think it does. (Did you mean ORDER BY instead?) It might help if you explained in words what you're trying to accomplish.
Anyway, I'm going to take a wild guess and suggest that this might be what you want:
SELECT
u.username, u.id, u.score, s.genre, s.songid, s.songTitle,
s.timeSubmitted, s.userid, s.insWanted, s.bounty,
COUNT(p.songid) AS trackCount
FROM songs s
LEFT JOIN users u ON u.id = s.userid
LEFT JOIN posttracks p ON p.songid = s.songid AND p.trackDeleted = 0
WHERE paid = 1 AND s.timeSubmitted >= ( CURDATE() - INTERVAL 60 DAY )
GROUP BY s.songid
ORDER BY s.timeSubmitted ASC
LIMIT 25
Edit: Fixed the COUNT() so that it will correctly return 0 if there are no matching tracks.
I have 2 tables, 1 with users and another with transactions. I am trying to display all users with the sum of their transactions.
The statement below is showing correctly except it will only include users that have transactions. How can I list all users, and if there is no transaction it should display sum as 0?
Here is the statement I am using:
SELECT
user.ID, user.FirstName, user.LastName,
user.Username,
SUM(transaction.Amount) As Total
FROM user
LEFT JOIN transaction
ON user.ID = transaction.runnerID
WHERE user.event = 'EventX'
AND user.Active = 'True'
AND (user.tran_result = '1' OR user.tran_result ='manual' )
AND transaction.event = 'EventX'
AND (transaction.tran_result = '1' OR transaction.tran_result ='manual' )
GROUP BY user.ID
ORDER BY user.LastName ASC
I assume it is the WHERE statement that is removing those rows, but if I remove the WHERE statement and place those details as part of the LEFT JOIN it seems to just hang trying to get results. (There are about 2,000 users and 40,000 transactions)
Thanks!
You need to move the criteria for the transaction table into the JOIN condition. Putting it into the WHERE clause effectively turns your outer join into an inner join:
SELECT ....
FROM user
LEFT JOIN transaction
ON user.ID = transaction.runnerID
AND transaction.event = 'EventX'
AND (transaction.tran_result = '1' OR transaction.tran_result ='manual' )
WHERE user.event = 'EventX'
AND user.Active = 'True'
AND (user.tran_result = '1' OR user.tran_result ='manual' )
GROUP BY user.ID
ORDER BY user.LastName ASC
Left Outer Join
Have you tried changing SUM(transaction.Amount) to SUM(ISNULL(transaction.Amount, 0))? This will ensure that a NULL value (i.e. no matching transactions) is treated as 0.