Create a combined list of objects in the same table using ActiveRecord
My application has groups and relationships between users.
Relationships are mutual, so in every group G, user A will have a label for user B and vice versa.
Here's the code for the Relationship model:
class Relationship < ApplicationRecord
belongs_to :group
belongs_to :user
belongs_to :receiver, class_name: "User", optional: true
On the Show User view (a.k.a. the "user profile" page), I'd like to create a table listing all the relationships, that would look like so.
| Group | User | Label for | Label from |
|-------|------|-----------|------------|
| Clowns| B | "Bozo" | "Ninny" |
| Dogs | C | "Rex" | |
| Tools | B | "Hammer" | "Wrench" |
So, with some help from @Rohit Patel's answer, I've progressed to the following syntax.
Relationship.select(:id, :group_id, :user_id, :receiver_id, :label, :'b.label as label_received').joins("left join relationships as b on relationships.receiver_id = b.user_id and relationships.group_id = b.group_id").where("relationships.user_id = 1")
It gets me the rows I need, but not the extra fields from the objects in b and groups.
The SQL to represent this would be:
SELECT a.group_name, a.user_id, a.label, b.name
FROM relationships AS a
LEFT JOIN
relationships AS b
ON a.user_id = b.receiver_id
WHERE a.user_id = "A"
I can't figure out how to do this with ActiveRecord.
What should I do?
ruby-on-rails activerecord
asked Nov 19 '18 at 6:19
JonoJono
178213
add a comment |
My application has groups and relationships between users.
Relationships are mutual, so in every group G, user A will have a label for user B and vice versa.
Here's the code for the Relationship model:
class Relationship < ApplicationRecord
belongs_to :group
belongs_to :user
belongs_to :receiver, class_name: "User", optional: true
On the Show User view (a.k.a. the "user profile" page), I'd like to create a table listing all the relationships, that would look like so.
| Group | User | Label for | Label from |
|-------|------|-----------|------------|
| Clowns| B | "Bozo" | "Ninny" |
| Dogs | C | "Rex" | |
| Tools | B | "Hammer" | "Wrench" |
So, with some help from @Rohit Patel's answer, I've progressed to the following syntax.
Relationship.select(:id, :group_id, :user_id, :receiver_id, :label, :'b.label as label_received').joins("left join relationships as b on relationships.receiver_id = b.user_id and relationships.group_id = b.group_id").where("relationships.user_id = 1")
It gets me the rows I need, but not the extra fields from the objects in b and groups.
The SQL to represent this would be:
SELECT a.group_name, a.user_id, a.label, b.name
FROM relationships AS a
LEFT JOIN
relationships AS b
ON a.user_id = b.receiver_id
WHERE a.user_id = "A"
I can't figure out how to do this with ActiveRecord.
What should I do?
ruby-on-rails activerecord
asked Nov 19 '18 at 6:19
JonoJono
178213
add a comment |
My application has groups and relationships between users.
Relationships are mutual, so in every group G, user A will have a label for user B and vice versa.
Here's the code for the Relationship model:
class Relationship < ApplicationRecord
belongs_to :group
belongs_to :user
belongs_to :receiver, class_name: "User", optional: true
On the Show User view (a.k.a. the "user profile" page), I'd like to create a table listing all the relationships, that would look like so.
| Group | User | Label for | Label from |
|-------|------|-----------|------------|
| Clowns| B | "Bozo" | "Ninny" |
| Dogs | C | "Rex" | |
| Tools | B | "Hammer" | "Wrench" |
So, with some help from @Rohit Patel's answer, I've progressed to the following syntax.
Relationship.select(:id, :group_id, :user_id, :receiver_id, :label, :'b.label as label_received').joins("left join relationships as b on relationships.receiver_id = b.user_id and relationships.group_id = b.group_id").where("relationships.user_id = 1")
It gets me the rows I need, but not the extra fields from the objects in b and groups.
The SQL to represent this would be:
SELECT a.group_name, a.user_id, a.label, b.name
FROM relationships AS a
LEFT JOIN
relationships AS b
ON a.user_id = b.receiver_id
WHERE a.user_id = "A"
I can't figure out how to do this with ActiveRecord.
What should I do?
ruby-on-rails activerecord
asked Nov 19 '18 at 6:19
JonoJono
178213
My application has groups and relationships between users.
Relationships are mutual, so in every group G, user A will have a label for user B and vice versa.
Here's the code for the Relationship model:
class Relationship < ApplicationRecord
belongs_to :group
belongs_to :user
belongs_to :receiver, class_name: "User", optional: true
On the Show User view (a.k.a. the "user profile" page), I'd like to create a table listing all the relationships, that would look like so.
| Group | User | Label for | Label from |
|-------|------|-----------|------------|
| Clowns| B | "Bozo" | "Ninny" |
| Dogs | C | "Rex" | |
| Tools | B | "Hammer" | "Wrench" |
So, with some help from @Rohit Patel's answer, I've progressed to the following syntax.
Relationship.select(:id, :group_id, :user_id, :receiver_id, :label, :'b.label as label_received').joins("left join relationships as b on relationships.receiver_id = b.user_id and relationships.group_id = b.group_id").where("relationships.user_id = 1")
It gets me the rows I need, but not the extra fields from the objects in b and groups.
The SQL to represent this would be:
SELECT a.group_name, a.user_id, a.label, b.name
FROM relationships AS a
LEFT JOIN
relationships AS b
ON a.user_id = b.receiver_id
WHERE a.user_id = "A"
I can't figure out how to do this with ActiveRecord.
What should I do?
ruby-on-rails activerecord
ruby-on-rails activerecord
asked Nov 19 '18 at 6:19
JonoJono
178213
asked Nov 19 '18 at 6:19
JonoJono
178213
edited Nov 19 '18 at 13:37
Jono
asked Nov 19 '18 at 6:19
JonoJono
178213
asked Nov 19 '18 at 6:19
JonoJono
178213
asked Nov 19 '18 at 6:19
JonoJono
178213
178213
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
Following should do:
Relationship.all(:select => "relationships.group_name, relationships.user_id, relationships.label, b.name",
:joins => "JOIN relationships AS b
ON relationships.user_id = b.receiver_id",
:conditions => ["relationships.user_id = 'A']
)
Let me know if it helps!
answered Nov 19 '18 at 7:22
eurodo061eurodo061
7114
add a comment |
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1 Answer
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Following should do:
Relationship.all(:select => "relationships.group_name, relationships.user_id, relationships.label, b.name",
:joins => "JOIN relationships AS b
ON relationships.user_id = b.receiver_id",
:conditions => ["relationships.user_id = 'A']
)
Let me know if it helps!
answered Nov 19 '18 at 7:22
eurodo061eurodo061
7114
add a comment |
Following should do:
Relationship.all(:select => "relationships.group_name, relationships.user_id, relationships.label, b.name",
:joins => "JOIN relationships AS b
ON relationships.user_id = b.receiver_id",
:conditions => ["relationships.user_id = 'A']
)
Let me know if it helps!
answered Nov 19 '18 at 7:22
eurodo061eurodo061
7114
add a comment |
Following should do:
Relationship.all(:select => "relationships.group_name, relationships.user_id, relationships.label, b.name",
:joins => "JOIN relationships AS b
ON relationships.user_id = b.receiver_id",
:conditions => ["relationships.user_id = 'A']
)
Let me know if it helps!
answered Nov 19 '18 at 7:22
eurodo061eurodo061
7114
Following should do:
Relationship.all(:select => "relationships.group_name, relationships.user_id, relationships.label, b.name",
:joins => "JOIN relationships AS b
ON relationships.user_id = b.receiver_id",
:conditions => ["relationships.user_id = 'A']
)
Let me know if it helps!
answered Nov 19 '18 at 7:22
eurodo061eurodo061
7114
answered Nov 19 '18 at 7:22
eurodo061eurodo061
7114
answered Nov 19 '18 at 7:22
eurodo061eurodo061
7114
answered Nov 19 '18 at 7:22
eurodo061eurodo061
7114
7114
add a comment |
add a comment |
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