I'm trying to connect two different types of users from the same users data table.
I have a database table with the following schema
agent_relationships
buyer_id
agent_id
I have a table with user data:
users
id
first name
last name
What i want is a data set that has the following:
buyer id first name
buyer id last name
agent id first name
agent id last name
I know im doing this incorrectly, but heres what I've attempted:
This one returns the same data for both buyer and agent, which i expected
select u1.first_name as buyerfirst,u1.last_name as buyerlast,u1.first_name as agentfirst,u1.last_name as agentlast from users u1 left join agent_relationships ar1 on ar1.buyer_id=u1.id left join agent_relationships ar2 on ar2.agent_id=u1.id
This one fails
select u1.first_name as buyerfirst,u1.last_name as buyerlast,u2.first_name as agentfirst,u2.last_name as agentlast from users u1,users u2 left join agent_relationships ar1 on ar1.buyer_id=u1.id left join agent_relationships ar2 on ar2.agent_id=u2.id
select BU.first_name, BU.last_name, AU.first_name, AU.last_name
from agent_relationships
left join users BU on buyer_id = BU.id
left join users AU on agent_id= AU.id
You need two join on user .. depending from agent_relationships
select u1.first_name as buyerfirst
,u1.last_name as buyerlast
,u2.first_name as agentfirst
,u2.last_name as agentlast
from agent_relationships ar
left join users u1 ar.buyer_id=u1.id
left join users u2 ar.agent_id=u1.id
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.
This is what I'd think is a fairly common pattern, but I'm just struggling with the appropiate query for it.
User Table
id
Member table
id
name
User Member link table
user_id
member_id
A user may exist in the user's table, but not have a row in the User Member link table.
I want to select all rows of the User table, and where a user has a link to a member in the user member link table to show the columns linked to them from the member table.
Here's what I've got, but it only gets the rows from the User table that are linked:
SELECT user.id, user.username, member.id, member.name
FROM users
LEFT JOIN user_member ON user.id = user_member.user_id
JOIN member ON user_member.member_id = member.id;
I should get something like this:
user.id user.username member.id member.name
1 bob null null
2 alice 10 Alice
3 jane 11 Jane
4 joe null null
Any suggestions?
I assume a member_id in the user_member table always has a corresponding row in the member table. First, join member and user_member. Second, join user.
SELECT user.id, user.username, member.id, member.name
FROM users
LEFT JOIN
(user_member INNER JOIN member ON user_member.member_id = member.id)
ON user.id = user_member.user_id;
Try using a CROSS JOIN
SELECT user.id, user.username, member.id, member.name
FROM users u
CROSS JOIN member m
LEFT JOIN user_member um
ON u.id= um.user_id
AND m.id= um.member_id
I have 3 tables
users
tickets
Activity
with relationship 1:n ---<-
users 1:n ticket (users can create many tickets)
ticket 1:n Activity (A tickets could have many activities)
Users 1:n Activity (A user can create many Activities that belong to a ticket)
I want to write a query that gives me
username ! ticket ! username ! activities
I try using Inner join but I only have the iduser (PK), and I need the column names.
I don't know how can I difference both names from users table. the first name was the user who create the ticket and the other the user who create the activity and both could be different.
try using alias.
select user.username as user_username, activities.username as act_username from ...
join on the users table twice, once with tickets, once with activities
select u1.username, a.ticket, u2.username, b.activity
from tickets a
join activities b on a.ticketid = b.ticketid
join users u1 on a.userid = u1.userid
join users u2 on b.userid = u2.userid
Consider the following :
**Table 1 - record**
id (int primary key),
addedby (int),
editedby (int)
**Table 2 - users**
id (int primary),
name (shorttext)
**Sample Records**
record
0 1 1
1 1 2
users
1 user1
2 user2
What I need is so do a join to to be able to show the following :
record.id, users.addedby, users.editedby
I tried, amongst others, the following :
select record.id, users.name, users.name from record left join users on record.addedby=users.id left join users on record.editedby=users.id
However, it's not even logical that that will work, so I am a bit stuck.
Any help would be much appreciated. Thank you.
Just join the same table twice. Nothing unusual. You just have to alias the tables to be able to refer to them independently.
select r.id, u1.name added, u2.name editor
from record r
inner join user u1
on r.addedby = u1.id
inner join user u2
on r.editedby = u2.id
heres a demo
Use aliasses:
select record.id, users1.name, users2.name
from record
left join users users1 on record.addedby=users1.id
left join users users2 on record.editedby=users2.id
My SQL is only returning one field when it should be returning one for each user.
Any idea where I'm going wrong? If you need additional information I can provide, but I'm just not sure where to go with this at the moment.
Here is my SQL:
SELECT uId, uForename, SUM(biProductPrice * biQuantity) AS uTotalSpent
FROM users
LEFT JOIN orders ON uId = ordUserId
LEFT JOIN basket ON ordUserId = bUserId
LEFT JOIN basketitems ON bId = biBasketId
WHERE ordStatus BETWEEN 4 AND 50
GROUP BY uId, uForename
any columns starting with u belong to the users table.
any columns starting with ord belong to the orders table.
any columns starting with b belong to the basket table.
any columns starting with bi belong to the basketitems table.
EDIT:
Everything now works fine except for my SUM, there are only 2 fields with an ordStatus between 4 and 50, so they are the only ones that apply, the biQuantity for one is 8 and the biProductPrice is 100, the other field has a biQuantity of 1 and a biProductPrice of 100, why is it returning a value of 400?
Group by the user and the sum will be returned for each one
SELECT users.id, users.name, SUM(biProductPrice) AS uTotalSpent
FROM users
LEFT JOIN orders ON uId = ordUserId
LEFT JOIN basket ON ordUserId = bUserId
LEFT JOIN basketitems ON bId = biBasketId
WHERE ordStatus BETWEEN 4 AND 50
group by users.uId, users.name
SELECT users.id, users.name, SUM(biProductPrice) AS uTotalSpent
FROM users
LEFT JOIN orders ON uId = ordUserId
LEFT JOIN basket ON ordUserId = bUserId
LEFT JOIN basketitems ON bId = biBasketId
WHERE ordStatus BETWEEN 4 AND 50
group by users.uId, users.name