i get an error got when i put this is my phpmyadmin sql,
error code #1052.
SELECT *
FROM users u
LEFT
JOIN user_tokens t
ON u.userid = u.id
LEFT
JOIN jt_campings_users cu
ON cu.userid = u.id
LEFT
JOIN campings c
ON c.user_id = u.id
WHERE id = 9271
You will have to give query hint to optimizer to where id is coming from because that might be possibility id is available in one or more tables :
WHERE u.id = 9271
So, the best practise to avoid such error is to use alias :
SELECT <column list> -- Do not use `*`, always qualify column list
FROM `users` u LEFT JOIN -- i removed LEFT JOIN user_tokens t as no mapping available
`jt_campings_users` jt
ON jt.userid = u.id LEFT JOIN
`campings` c
ON c.user_id = users.id
WHERE u.id = 9271;
Related
I am using the expression below to find out which 'resource' type customers have 'work_resource' that are active.
WITH cte_ss AS (SELECT wr.user_id
FROM work w
JOIN work_resource wr ON wr.work_id = w.id
WHERE wr.work_resource_status_type_code = 'active'
),
SELECT u.uuid
FROM user u
JOIN company c ON c.id = u.company_id
LEFT JOIN cte_ss on cte_ss.user_id = u.id
AND c.customer_type = 'resource'
White trying to run this, I get the following error
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SELECT u.uuid
FROM user u
JOIN company c ON c.id = u.company_id
LEFT JOIN cte_ss' at line 6
Both the individual queries (without the LEFT JOIN) are working, so not sure what I am doing wrong here
A cte would look like this
But as i don't know nothing about your tables, you have to figure it out yourself
WITH cte_ss AS (
SELECT
user_id
FROM work w
JOIN work_resource wr ON wr.work_id = w.id
WHERE wr.work_resource_status_type_code = 'active'
)
SELECT u.uuid
FROM user u
JOIN company c ON c.id = u.company_id
LEFT JOIN cte_ss on cte_ss.user_id = u.id
AND c.customer_type = 'resource'
I have a wordpress site that is used to store student grades on various lessons (from the quizzes on the site). I am trying to create a query that will pull out all of the lessons for all students in a certain group (using buddypress groups) and the students grades in each lesson.
I have created this query:
SELECT u.display_name, p.post_title, cm.meta_value
FROM wp_users u
JOIN wp_bp_groups_members gm
ON u.ID = gm.user_id
JOIN wp_comments c
ON u.ID = c.user_id
JOIN wp_commentmeta cm
ON c.comment_ID = cm.comment_id
JOIN (SELECT * FROM wp_posts WHERE post_type LIKE 'lesson') p
ON c.comment_post_id = p.ID
WHERE gm.group_id = 4 AND cm.meta_key LIKE 'grade'
This currently returns all the grades for all students in a group in the lessons they have attempted the test. However it does not return any lessons they have not attempted the test in, which I need still.
Just to be clear: lessons are posts, grades are meta_values in a record with a meta_key of 'grades'. These are stored as comments, and comment_meta.
I hope this is all clear and you can help. Thanks.
After Ollie Jones help I made this:
SELECT u.display_name, p.post_title, IFNULL(cm.meta_value,'--nothing--') grade
FROM wp_users u
JOIN wp_comments c
LEFT JOIN wp_commentmeta cm
ON c.comment_ID = cm.comment_id AND cm.meta_key = 'grade'
JOIN wp_bp_groups_members gm
ON u.ID = gm.user_id
JOIN wp_posts p
ON c.comment_post_id = p.ID
WHERE gm.group_id = 4 AND p.post_type LIKE 'lesson'
Which almost works but returns all student grades, not just the ones in the group (though it only gives the one name of the student in the group).
This is the familiar key/value store problem, that comes up with commentmeta, postsmeta, and usermeta. When you JOIN two tables and the left one might not have a corresponding row, you need to use LEFT JOIN. When the left one is a key/value table, you need to adjust the ON condition accordingly. Finally, when you LEFT JOIN two tables and there's no matching row in it it, you get back NULLs for those columns, so you must allow for that.
So this kind of SQL pattern will do the trick for you
SELECT whatever, IFNULL(cm.meta_value,'--nothing--') grade
FROM whatever
LEFT JOIN wp_comments c ON whatever.id = c.user_id
LEFT JOIN wp_commentmeta cm ON c.comment_id = cm.comment_id
AND cm.meta_key = 'grade'
JOIN whatever
Is there a user_id in your comments table? I dont see where you joined which user posted which comment. So when you join the group_members to the users table, you are specifying which users to show, but since you are not joining on user id when you join to your comments table, it will show all the comments for all the users. Im not sure if this will work for your table, but try:
SELECT u.display_name, p.post_title, IFNULL(cm.meta_value,'--nothing--') grade
FROM wp_users u
LEFT JOIN wp_comments c
JOIN wp_commentmeta cm
ON c.comment_ID = cm.comment_id AND cm.meta_key = 'grade'
JOIN wp_bp_groups_members gm
ON c.user_ID = gm.user_id
ON u.user_id = c.user_id
JOIN wp_posts p
ON c.comment_post_id = p.ID
WHERE gm.group_id = 4 AND p.post_type LIKE 'lesson'
Hope this helps!
How would I do following in MySQL:
I have 3 tables:
user: id
communication: id, creation_date
user_communication: user_id, communication_id
Now I want to select all users that have had no communication since a given date.
Following is what I have now, but I'm stuck on how to get what I described above.
SELECT DISTINCT u.id FROM user u
LEFT JOIN user_communication uc ON uc.user_id = u.id
LEFT JOIN communication c ON c.id = uc.communication_id
WHERE c.creation_date < '2013-8-1';
The where condition is undoing the left join. The initial solution would be to move it to the on clause:
SELECT DISTINCT u.id FROM user u
LEFT JOIN user_communication uc ON uc.user_id = u.id
LEFT JOIN communication c ON c.id = uc.communication_id and c.creation_date < '2013-8-1';
But this doesn't do what you want. This retrieves all records. If you had a creation date field in the select clause, it would be NULL when there is record before that date.
For no communication since that date, you can do a "double" negative" query. Look for records that are since that date, and return the mismatches:
SELECT DISTINCT u.id
FROM user u LEFT JOIN
user_communication uc
ON uc.user_id = u.id LEFT JOIN
communication c
ON c.id = uc.communication_id and c.creation_date >= '2013-08-01'
WHERE c.creation_date is NULL;
EDIT:
I see. The problem is a little more subtle than my answer above. Each user has multiple communications, so none can be later. The following query tests this by grouping by u.id and then checking that there are no non-NULL values from the above join:
SELECT u.id
FROM user u LEFT JOIN
user_communication uc
ON uc.user_id = u.id LEFT JOIN
communication c
ON c.id = uc.communication_id and c.creation_date >= '2012-08-01'
group by u.id
having min(c.creation_date is null) = 1;
SELECT DISTINCT u.id FROM user u
LEFT JOIN user_communication uc ON uc.user_id = u.id
LEFT JOIN (SELECT * FROM communication WHERE creation_date < '2013-8-1') c
ON c.id = uc.communication_id
WHERE c.id is NULL;
After some research and help I have following query, which seems to work:
SELECT DISTINCT(u.id)
FROM user u
WHERE (SELECT coalesce(max(c.creation_date), '1900-01-01 00:00:00') last_creation_date
FROM user inneru
LEFT JOIN user_communication uc ON uc.user_id = inneru.id
LEFT JOIN communication c ON c.id = uc.communication_id
WHERE inneru.id = u.id) < '2012-08-01'
SQLFiddle: http://sqlfiddle.com/#!2/5dfad/10
I have a query that I know it should atleast return one row. How can i modify my follow query to make sure that album returns data. thanks for any help.
Query Here. I know that Album has a row and I need to return it.
select distinct p.*,
a.ID as parentalbumid,a.CreatorID as albumcreatorid,a.AlbumName,a.AlbumDescription,a.AlbumDefaultImageURL,a.Private,a.DateCreated,a.AdultContent,a.PasswordProtected,a.AllowTags,a.TypeID,a.AlbumAutoID,
mainuser.Username as mainuserusername,mainuser.ID as mainuserid,mainuser.PictureUrl as mainuserpictureurl,
c.ID as commentID,c.PhotoID as commentphotoid,c.OutputMessage,c.CommentDate,
t.ID as tagID,t.PhotoID as tagphotoid,t.UserID,t.TextTag,t.LeftLocation,t.TopLocation,
u.ID as userid,u.Username,u.FirstName,u.LastName,u.PictureUrl
from photos p
inner join albums a on a.ID = p.AlbumID
inner join users mainuser on mainuser.ID = p.UserID
left join comments c on c.PhotoID = p.ID
left join tags t on t.PhotoID = p.ID
left join users u on u.ID = c.CommentBy
where a.AlbumAutoID = 3
order by p.DateUploaded desc;
Use only LEFT JOINs (and put the table albums as the first table of your FROM):
select distinct p.*,
a.ID as parentalbumid,a.CreatorID as albumcreatorid,a.AlbumName,a.AlbumDescription,a.AlbumDefaultImageURL,a.Private,a.DateCreated,a.AdultContent,a.PasswordProtected,a.AllowTags,a.TypeID,a.AlbumAutoID,
mainuser.Username as mainuserusername,mainuser.ID as mainuserid,mainuser.PictureUrl as mainuserpictureurl,
c.ID as commentID,c.PhotoID as commentphotoid,c.OutputMessage,c.CommentDate,
t.ID as tagID,t.PhotoID as tagphotoid,t.UserID,t.TextTag,t.LeftLocation,t.TopLocation,
u.ID as userid,u.Username,u.FirstName,u.LastName,u.PictureUrl
from albums a
left join photos p on a.ID = p.AlbumID
left join users mainuser on mainuser.ID = p.UserID
left join comments c on c.PhotoID = p.ID
left join tags t on t.PhotoID = p.ID
left join users u on u.ID = c.CommentBy
where a.AlbumAutoID = 3
order by p.DateUploaded desc;
I looked at the answers of others having the same problem, but I can't figure out how to fix the "Not unique table/alias".
SELECT m.*, u.*
FROM ".TABLE_PREFIX."users_medals u
LEFT JOIN ".TABLE_PREFIX."medals m ON u.medal_id = m.medal_id
WHERE u.user_id IN (".$post['uid'].")
AND m.medal_level = (
SELECT MAX(".TABLE_PREFIX."medals.medal_level) FROM ".TABLE_PREFIX."medals
LEFT JOIN ".TABLE_PREFIX."medals ON ".TABLE_PREFIX."users_medals.medal_id = ".TABLE_PREFIX."medals.medal_id
WHERE ".TABLE_PREFIX."users_medals.user_id = u.user_id
AND ".TABLE_PREFIX."medals.medal_type = m.medal_type
)
TABLE_PREFIX is what my script uses to define the database table prefix.
In your sub-query
LEFT JOIN ".TABLE_PREFIX."medals
I think that should be
LEFT JOIN ".TABLE_PREFIX."users_medals
In the subquery you have two medals tables without aliases. I think the FROM ".TABLE_PREFIX."medals should be FROM ".TABLE_PREFIX."users_medals:
SELECT m.*, u.*
FROM ".TABLE_PREFIX."users_medals u
LEFT JOIN ".TABLE_PREFIX."medals m ON u.medal_id = m.medal_id
WHERE u.user_id IN (".$post['uid'].")
AND m.medal_level = (
SELECT MAX(".TABLE_PREFIX."medals.medal_level) FROM ".TABLE_PREFIX."users_medals
LEFT JOIN ".TABLE_PREFIX."medals ON ".TABLE_PREFIX."users_medals.medal_id = ".TABLE_PREFIX."medals.medal_id
WHERE ".TABLE_PREFIX."users_medals.user_id = u.user_id
AND ".TABLE_PREFIX."medals.medal_type = m.medal_type
)