Є 2-і таблиці: DEPT (dept_id, dept_name); EMP (emp_id, dept_id, name, salary); Який із наведених запитів є помилковим?

Question

Answer

d.  SELECT dept_id, dept_name, COUNT(dept_id)  FROM dept;

Answer

a.  SELECT dept.dept_id, dept.dept_name, emp.name, emp.salary  FROM dept RIGHT OUTER JOIN emp ON (dept. dept_id = emp. dept_id);

Answer

b.  SELECT dept.dept_id, dept.dept_name, emp.name, emp.salary  FROM dept, emp WHERE dept. dept_id = emp. dept_id;

Answer

c.  SELECT emp.dept_id, SUM( emp.salary)  FROM emp GROUP BY emp. dept_id;

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