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MySQL INNER JOIN select only one row from second table
...LECT a.*, c.*
FROM users a
INNER JOIN payments c
ON a.id = c.user_ID
INNER JOIN
(
SELECT user_ID, MAX(date) maxDate
FROM payments
GROUP BY user_ID
) b ON c.user_ID = b.user_ID AND
c.date = b.maxDate
WHERE a.package = 1
...
Laravel Migration Change to Make a Column Nullable
I created a migration with unsigned user_id . How can I edit user_id in a new migration to also make it nullable() ?
9 ...
Rails Model find where not equal
...rails.org/active_record_querying.html#not-conditions)
GroupUser.where.not(user_id: me)
In Rails 3.x
GroupUser.where(GroupUser.arel_table[:user_id].not_eq(me))
To shorten the length, you could store GroupUser.arel_table in a variable or if using inside the model GroupUser itself e.g., in a scop...
Rails :include vs. :joins
...ng), Age(integer). The Comment model has the following attributes:Content, user_id. For a comment a user_id can be null.
Joins:
:joins performs a inner join between two tables. Thus
Comment.joins(:user)
#=> <ActiveRecord::Relation [#<Comment id: 1, content: "Hi I am Aaditi.This is my ...
Migration: Cannot add foreign key constraint
...) {
$table->increments('id', true);
$table->integer('user_id')->unsigned();
$table->string('priority_name');
$table->smallInteger('rank');
$table->text('class');
$table->timestamps('timecreated');
});
Schema::table('priorit...
Can Flask have optional URL parameters?
...
Another way is to write
@user.route('/<user_id>', defaults={'username': None})
@user.route('/<user_id>/<username>')
def show(user_id, username):
pass
But I guess that you want to write a single route and mark username as optional? If that's t...
Possible to do a MySQL foreign key to one of two possible tables?
...signate which target table is referenced.
CREATE TABLE popular_places (
user_id INT NOT NULL,
place_id INT NOT NULL,
place_type VARCHAR(10) -- either 'states' or 'countries'
-- foreign key is not possible
);
There's no way to model Polymorphic Associations using SQL constraints. A foreig...
generate model using user:references vs user_id:integer
... that this is the case:
:001 > Micropost
=> Micropost(id: integer, user_id: integer, created_at: datetime, updated_at: datetime)
The second command adds a belongs_to :user relationship in your Micropost model whereas the first does not. When this relationship is specified, ActiveRecord wi...
SQL query for finding records where count > 1
...have more than one payment per day with the same account number
SELECT
user_id ,
COUNT(*) count
FROM
PAYMENT
GROUP BY
account,
user_id ,
date
Having
COUNT(*) > 1
Update
If you want to only include those that have a distinct ZIP you can get a distinct set first and then perform you HAV...
What is the difference between a stored procedure and a view?
...hen and why to use each.
Say I have two tables:
tbl_user, with columns: user_id, user_name, user_pw
tbl_profile, with columns: profile_id, user_id, profile_description
So, if I find myself querying from those tables A LOT... instead of doing the join in EVERY piece of SQL, I would define a view...