#案例：返回location_id是1400或1700的部门中的所有员工
SELECT last_name
FROM employees
WHERE department_id IN(
SELECT DISTINCT department_id
FROM departments
WHERE location_id IN (1400,1700)
);
#案例：返回其他工种中比job_id为'IT_PROG'部门任一工资低的员工的员工号、姓名、job_id和salary
SELECT DISTINCT employee_id,last_name,job_id,salary
FROM employees
WHERE salary<ANY(
SELECT DISTINCT salary
FROM employees
WHERE job_id='IT_PROG'
) AND job_id <>'IT_PROG' ;
或者
SELECT DISTINCT employee_id,last_name,job_id,salary
FROM employees
WHERE salary<(
SELECT DISTINCT MAX(salary)
FROM employees
WHERE job_id='IT_PROG'
) AND job_id <>'IT_PROG' ;
#案例：返回其他工种中比job_id为'IT_PROG'部门所有工资低的员工的员工号、姓名、job_id和salary
SELECT DISTINCT employee_id,last_name,job_id,salary
FROM employees
WHERE salary<ALL(
SELECT DISTINCT salary
FROM employees
WHERE job_id='IT_PROG'
) AND job_id <>'IT_PROG' ;
或者
SELECT DISTINCT employee_id,last_name,job_id,salary
FROM employees
WHERE salary<(
SELECT DISTINCT MIN(salary)
FROM employees
WHERE job_id='IT_PROG'
) AND job_id <>'IT_PROG' ;
