인동머스크

Table: Scores+-------------+---------+| Column Name | Type |+-------------+---------+| student_id | int || subject | varchar || score | int || exam_date | varchar |+-------------+---------+(student_id, subject, exam_date) is the primary key for this table.Each row contains information about a student's score in a specific subject on a particular exam date. score is betwee..

Table: transactions+------------------+------+| Column Name | Type | +------------------+------+| transaction_id | int || amount | int || transaction_date | date |+------------------+------+The transactions_id column uniquely identifies each row in this table.Each row of this table contains the transaction id, amount and transaction date.Write a solution to find the sum of amo..

Table: UserActivity+------------------+---------+| Column Name | Type | +------------------+---------+| user_id | int || activity_date | date || activity_type | varchar || activity_duration| int |+------------------+---------+(user_id, activity_date, activity_type) is the unique key for this table.activity_type is one of ('free_trial', 'paid', 'cancelled').activ..

Table: Samples+----------------+---------+| Column Name | Type | +----------------+---------+| sample_id | int || dna_sequence | varchar || species | varchar |+----------------+---------+sample_id is the unique key for this table.Each row contains a DNA sequence represented as a string of characters (A, T, G, C) and the species it was collected from.Biologists are studyin..