I am using MySQL.
I have three tables named ratings, users and one master table master_entityType.
Depending on the values from entityTable column of the master_entityType table, I have to join with another table. If the values from master_entityType is "Blogs", I have to join with blogs table. If the values from master_entityType is "items", I have to join with items table.
SELECT * FROM ratings AS r
LEFT JOIN users AS u ON u.userID = r.userID
LEFT JOIN master_entityType AS ms ON ms.entityTypeID = r.entityTypeID
CASE ms.entityTable
WHEN 'Blogs' THEN INNER JOIN blogs AS b ON b.blogID = r.entityID
END
WHERE r.entityTypeID = '10' AND r.entityID = '1' AND r.userID = '1'
While using the above query I am getting error, please suggest some step to get that query to work.
Structure of the table are as follows,
In users table,
UserID userName isActive
1 Dinesh 1
2 Kumar 1
In ratings table,
ratingID entityID entityTypeID userID rating
1 1 1 1 5
2 4 2 1 4
In master_entityType table,
entityTypeID entityTable entityTypeName entityTypeDescription active
1 blogs Blogs Null 1
2 items Items Null 1
In Items table,
ItemID name collection active
4 pencil 12 1
5 pen 06 1
In blogs table,
blogID name active
1 socail 1
2 private 1
Your design is strange, so performance is likely to be poor.
UNION ALL two tables together and join with the result. Something like this.
If MySQL has views, then create view that unions Items and Blogs table and use the view in other queries. It makes the queries easier to read, understand and maintain.
Here is SQL Fiddle. I adjusted the WHERE condition in the fiddle, because sample data doesn't have any rows with entityTypeID = 10.
SELECT *
FROM
ratings AS r
LEFT JOIN users AS u ON u.userID = r.userID
LEFT JOIN master_entityType AS ms ON ms.entityTypeID = r.entityTypeID
INNER JOIN
(
SELECT
ItemID AS EntityID
,'Items' AS EntityTypeName
,name
,active
FROM items
UNION ALL
SELECT
BlogID AS EntityID
,'Blogs' AS EntityTypeName
,name
,active
FROM blogs
) AS Entities ON
Entities.EntityTypeName = ms.entityTypeName
AND Entities.EntityID = r.entityID
WHERE r.entityTypeID = '10' AND r.entityID = '1' AND r.userID = '1'
Related
The main table has 4 columns:
User Activity Table
userActivityId userId therapistId activityId
1 1 1 1
Each of these columns is a table and these values are all foreign keys.
Basically im trying to run a query that will join to the users table and pull their first and last name based off the user Id.Same thing with therapist - join to the therapist table, pull first + last name.And finally Join to the Activity table and pull the activity name and path from the activity Id
The other tables look like this:
User Table
userId fName lName
Therapist Table
therapistId therapistFirstName therapistLastName
Activity Table
activityId activityTitle activityPath
So far my query looks like
SELECT
User_Activities.userId,
User_Activities.therapistId,
User_Activities.activityId,
Activities.activityTitle,
Activities.activityPath,
Users.fName,
users.lName,
Therapists.therapistFirstName,
Therapists.therapistLastName
FROM
User_Activities
INNER JOIN Users
ON User_Activities.userId = Users.userId
INNER JOIN Therapists ON
User_Activities.therapistId = Therapists.therapistId
INNER JOIN Activities ON
Activities.activityId = User_Activities.userActivityId
WHERE
User_Activities.userId = 1;
When I run this query It only returns 1 row as a result. However there are two activities in the User_Activites table assigned to userId 1.
If I change : INNER JOIN Activities ON
Activities.activityId = User_Activities.userActivityId
from an INNER JOIN to the LEFT JOIN it will display the second row, however the activityTitle and activityPath will be displayed as NULL in the second row.
userActivityId userId therapistId activityId activityId activityTitle activityPath fName lName therapistFirstName therapistLastName
1 1 1 1 1 Brain GZZ0zpUQ S C M D
11 1 1 1 NULL NULL NULL S C M D
You have pretty much answered your question. The second activity does not have a valid ActivityId.
If you want all activities for a user, then you should phrase the query as:
SELECT . . .
FROM Users u LEFT JOIN
User_Activities ua
ON ua.userId = u.userId LEFT JOIN
Therapists t
ON ua.therapistId = t.therapistId LEFT JOIN
Activities a
ON a.activityId = ua.userActivityId
WHERE u.userId = 1;
You want to start with the table where you want to keep all the rows. Then use LEFT JOIN to bring in other tables.
Two other changes of note:
Table aliases are used to simplify reading and writing the query. The SELECT needs to change to use the aliases.
The WHERE clause refers to the Users table rather than UserActivities.
I have a user table in the database where all users of the system are stored.
The table has a user_id and a business_name and a first_name.
Some users are merchants and get a business name,
some users are consumers and get a first name.
In a second table I have transactions with a user_id and a merchant_id (which are defining the transaction) and an amount. Both ids reference to user table.
Table users:
user_id bus_name first_name role_id
1 Thomas 10
2 comp1 7
3 Peter 10
4 comp2 7
(role_id is defining with 10=consumer, 7=merchant)
Table transactions:
trans_id amount user_id merchant_id
1 12 1 2
2 23 3 2
3 34 3 4
4 19 1 4
Now I want to have a query with a result as one table:
This table should contain the transaction with amount, user_id, first_name, merchant_id and bus_name.
I want to get this result:
trans_id amount user_id first_name merchant_id bus_name
1 12 1 Thomas 2 comp1
2 23 3 Peter 2 comp1
3 34 3 Peter 4 comp2
4 19 1 Thomas 4 comp2
I have the problem that either I get only the first_name and empty bus_name or I get only the bus_name but empty first_name.
I am using a left join:
...
left join `users`
on(
(`transactions`.`user_id` = `users`.`user_id`)
)
...
But for this I would get for user_id=1 the first_name=Thomas and the bus_name='' would be empty because I only reference to one line in table and not also to different user with user_id=2.
But I want to say something like:
for trans_id=1
get first_name FROM users WHERE transactions.user_id = users.user_id
AND
get bus_name FROM users WHERE transactions.merchant_id = users.user_id
Thanks for your help, I tried so many things but it does not work.
You have to join the user table twice:
SELECT t.*, u.first_name, m.bus_name
FROM transactions t
JOIN users as u
ON t.user_id = u.user_id
JOIN users as m
ON t.merchant_id = m.merchant_id
you could use a duoble join in users table
select a.trans_id, a.amount , a.user_id, b.first_name, a.merchant_id, c. bus_name
from transactions a
inner join users b on a.user_id = b.user_id and b.role_id = 10
inner join users c on a.merchant_id = c.user_id and c.role_id = 7
To join the user table twice worked fine. With "left join users as consumer" I create a kind of a virtual users table called "consumer", this one is joined. Of course in select I had to adjust table name as well. Same for second "virtual" table od users, called "merchant".
select
`transactions`.`trans_id` AS `trans_id`,
`transactions`.`merchant_id` AS `merchant_id`,
`merchant`.`bus_name` AS `bus_name`,
`transactions`.`user_id` AS `user_id`,
`consumer`.`first_name` AS `first_name`,
`cards`.`card_id` AS `card_id`,
`cards`.`serial_no` AS `serial_no`
from (
`transactions`
left join `cards`
on(
(`cards`.`card_id` = `transactions`.`card_id`)
)
left join `users` as consumer
on(
(`consumer`.`user_id` = `transactions`.`user_id`)
)
left join `users` as merchant
on(
(`merchant`.`user_id` = `transactions`.`merchant_id`)
)
)
Consider the following data set:
users table:
id (int) email (string)
1 first#example.com
2 second#example.com
order_items table:
id (int) user_id (int) generation (string)
1 1 '11'
2 1 '12'
2 1 '12.50'
3 1 '16.00'
4 2 '11'
5 2 '12'
UPDATED question
How can I select users which doesn't have order_items with generation 16.00 and have at least one order_item?
So:
email
second#example.com
1) Returning Users who don't have order item with generation 16 included users with no orders at all.
Assuming you have some kind of id column in order_items table:
select u.* from users u
left outer join order_items oi on (u.id = oi.user_id and oi.generation = 16)
where oi.id is null;
Otherwise use whatever primary key you have in order_items in the where condition to be NULL.
Updated to include answer for the question in comment
2) Returning users who don't have order item with generation 16 but have least one order.
select distinct u.* from users u
left outer join order_items oi16 on (u.id = oi.user_id and oi.generation = 16)
join order_items oiother on (u.id = oiother.user_id and oiother.generation != 16)
where oi16.id is null;
We do the filtering by using a second (normal) join which only returns users where it finds matching rows from the order_items table.
Here we need the distinct because the second join will multiply your rows depending on how many other orders the user have.
Alternatively you can also do a count or sum like this:
select u.*, count(distinct oiother.id) from users u
left outer join order_items oi16 on (u.id = oi.user_id and oi.generation = 16)
join order_items oiother on (u.id = oiother.user_id and oiother.generation != 16)
where oi16.id is null
group by u.id;
This will give you also how many other order items each returned user have. Or omit the count completely and using group by just to return distinct items.
You can use NOT EXISTS() like this:
SELECT * FROM Users u
WHERE NOT EXISTS(SELECT 1 FROM order_items o
WHERE o.userid = u.id
AND o.generation = 16)
That checks if there is a record for this user with order.generation = 16, and if there isn't it selects him.
Or not in()
SELECT * FROM Users u
WHERE u.id NOT IN(SELECT userid FROM order_items o
WHERE o.generation = 16)
That selects the list of users who have order.generation = 16, and select every id except them.
Following query should give you the desired output:
*update*
changed query as per the new result format in the question
As we want the data only from generation table, join with user table is not needed anymore. Here's the updated query:
select id, generation
from mytable where id not in (
select id from mytable
where generation = 16
group by id
);
Here is the SQL fiddle for it.
I have 2 tables named user and userFriend. I want all user from user table, and specific member from userFriend table. Then I want to join both of them...
user
userID userName
1 aaa
2 bbb
3 ccc
4 ddd
5 eee
userFriend
userFriendID userID friendUserID
1 1 2
2 2 3
3 1 4
4 4 2
So if my userID = 1,
then I want result like
userID userName userFriendID friendUserID
2 bbb 1 2
3 ccc NULL NULL
4 ddd 3 4
5 eee NULL NULL
so in this way I want conditional for 2nd table, I only want to join 2nd table having userID = 1 with 1st table using left join.
It's an unconventional thing to ask for... but this gives you the results you want.
SELECT u.userID, u.userName, uf.userFriendID, uf.friendUserID
FROM user u
LEFT JOIN userFriend uf ON u.userID = uf.friendUserID AND uf.userID =1
WHERE u.userID !=1
For what you want you dont need a query from both tables. Just using userFriend will give you the data. You'll need the user table for names only.
SELECT DISTINCT userID FROM userFriend
WHERE friendUserID = ?
this will give you all users that have that specific friend that you need.
Optionally you can add a INNER JOIN to see what are the names:
SELECT DISTINCT f.userID, u.name
FROM userFriend f
INNER JOIN users u ON u.userID = f.userID
WHERE friendUserID = ?
UPDATE
A comment about your structure. You don't need the userFriendID. The combination of userID and friend ID can be your key.
UPDATE of the query
SELECT * FROM users u
LEFT JOIN userFriend f on u.userID = f.userID
WHERE f.friendUserID = ?
This will return you all users that have the friend X. The left join is not important in this query. This specific condition is making it irrelevant.
To get exactly what you want you need to execute this.
SELECT * FROM users u
LEFT JOIN (
SELECT DISTINCT * FROM userFriend f
WHERE friendID = 4
) x ON u.id = x.userId
It can be done using a subquery, but I dont think is the most logical way of organizing your tables.
I'm working on a mysql query in a Drupal database that pulls together users and two different cck content types. I know people ask for help with groupwise maximum queries all the time... I've done my best but I need help.
This is what I have so far:
# the artists
SELECT
users.uid,
users.name AS username,
n1.title AS artist_name
FROM users
LEFT JOIN users_roles ur
ON users.uid=ur.uid
INNER JOIN role r
ON ur.rid=r.rid
AND r.name='artist'
LEFT JOIN node n1
ON n1.uid = users.uid
AND n1.type = 'submission'
WHERE users.status = 1
ORDER BY users.name;
This gives me data that looks like:
uid username artist_name
1 foo Joe the Plumber
2 bar Jane Doe
3 baz The Tooth Fairy
Also, I've got this query:
# artwork
SELECT
n.nid,
n.uid,
a.field_order_value
FROM node n
LEFT JOIN content_type_artwork a
ON n.nid = a.nid
WHERE n.type = 'artwork'
ORDER BY n.uid, a.field_order_value;
Which gives me data like this:
nid uid field_order_value
1 1 1
2 1 3
3 1 2
4 2 NULL
5 3 1
6 3 1
Additional relevant info:
nid is the primary key for an Artwork
every Artist has one or more Artworks
valid data for field_order_value is NULL, 1, 2, 3, or 4
field_order_value is not necessarily unique per Artist - an Artist could have 4 Artworks all with field_order_value = 1.
What I want is the row with the minimum field_order_value from my second query joined with the artist information from the first query. In cases where the field_order_value is not valuable information (either because the Artist has used duplicate values among their Artworks or left that field NULL), I would like the row with the minimum nid from the second query.
The Solution
Using divide and conquer as a strategy and mysql views as a technique, and referencing this article about groupwise maximum queries, I solved my problem.
Create the View
# artists and artworks all in one table
CREATE VIEW artists_artwork AS
SELECT
users.uid,
users.name AS artist,
COALESCE(n1.title, 'Not Yet Entered') AS artist_name,
n2.nid,
a.field_image_fid,
COALESCE(a.field_order_value, 1) AS field_order_value
FROM users
LEFT JOIN users_roles ur
ON users.uid=ur.uid
INNER JOIN role r
ON ur.rid=r.rid
AND r.name='artist'
LEFT JOIN node n1
ON n1.uid = users.uid
AND n1.type = 'submission'
LEFT JOIN node n2
ON n2.uid = users.uid
AND n2.type = 'artwork'
LEFT JOIN content_type_artwork a ON n2.nid = a.nid
WHERE users.status = 1;
Query the View
SELECT
a2.uid,
a2.artist,
a2.artist_name,
a2.nid,
a2.field_image_fid,
a2.field_order_value
FROM (
SELECT
uid,
MIN(field_order_value) AS field_order_value
FROM artists_artwork
GROUP BY uid
) a1
JOIN artists_artwork a2
ON a2.nid = (
SELECT
nid
FROM artists_artwork a
WHERE a.uid = a1.uid
AND a.field_order_value = a1.field_order_value
ORDER BY
uid ASC, field_order_value ASC, nid ASC
LIMIT 1
)
ORDER BY artist;
A simple solution to this can be to create views in your database that can then be joined together. This is especially useful if you often want to see the intermediate data in the same way in some other place. While it is possible to mash together the one huge query, I just take the divide and conquer approach sometimes.