data_yep

[문제]  [MySQL]SELECT transaction_date , SUM(CASE WHEN MOD(amount, 2) = 1 THEN amount ELSE 0 END) AS odd_sum , SUM(CASE WHEN MOD(amount, 2) = 0 THEN amount ELSE 0 END) AS even_sumFROM transactionsGROUP BY transaction_dateORDER BY transaction_date ASC

[문제]  [MySQL]SELECT teacher_id , COUNT(DISTINCT subject_id) AS cntFROM TeacherGROUP BY teacher_id

[문제]  [MySQL]SELECT employee_idFROM EmployeesWHERE salary

[문제]  [MySQL]SELECT employee_idFROM EmployeesWHERE employee_id NOT IN (SELECT employee_id FROM Salaries)UNIONSELECT employee_idFROM SalariesWHERE employee_id NOT IN (SELECT employee_id FROM Employees)ORDER BY employee_id ASC

[문제]  [MySQL]WITH Action_cnt AS ( SELECT s.user_id , c.action , CASE WHEN c.action = 'confirmed' THEN 1 ELSE 0 END AS action_cnt FROM Signups AS s LEFT JOIN Confirmations AS c ON s.user_id = c.user_id)SELECT user_id , ROUND(SUM(action_cnt) / COUNT(*), 2) AS confirmation_rateFROM Action_cntGROUP BY user_id

[문제]  [MySQL]SELECT 'Low Salary' AS category , COUNT(*) AS accounts_countFROM AccountsWHERE income = 20000 AND income 50000

[문제]  [MySQL]SELECT user_id , MAX(time_stamp) AS last_stampFROM LoginsWHERE YEAR(time_stamp) = 2020GROUP BY user_id

[문제]  [MySQL]SELECT employee_id , CASE WHEN MOD(employee_id, 2) = 1 AND name NOT LIKE 'M%' THEN salary ELSE 0 END AS bonusFROM EmployeesORDER BY employee_id ASC

[문제]  [MySQL]SELECT product_id , 'store1' AS store , store1 AS priceFROM ProductsWHERE store1 IS NOT NULLUNION ALLSELECT product_id , 'store2' AS store , store2 AS priceFROM ProductsWHERE store2 IS NOT NULLUNION ALLSELECT product_id , 'store3' AS store , store3 AS priceFROM ProductsWHERE store3 IS NOT NULL

[문제]  [MySQL]SELECT employee_id , department_idFROM EmployeeWHERE primary_flag = 'Y'UNIONSELECT employee_id , department_idFROM EmployeeWHERE employee_id NOT IN (SELECT employee_id FROM Employee WHERE primary_flag = 'Y')