[打卡]谷加伟——子查询习题

# 单行子查询

# 单行操作符 = ！= <>不等于 > >= < <=

# 习题：查询公司大于149号员工工资的员工信息
SELECT employee_id,last_name,salary
FROM employees
WHERE salary > (
SELECT salary
FROM employees
WHERE employee_id=149
);

#习题：返回job_id与141号员工相同，salary比143号员工多的员工姓名，job_id和工资

SELECT last_name,job_id,salary
FROM employees
WHERE job_id = (
SELECT job_id
FROM employees
WHERE employee_id = 141
)
AND salary >= (
SELECT salary
FROM employees
WHERE employee_id=143
)

# 中英互换

# 习题：返回公司工资最少的员工的last_name,job-id和salary

SELECT last_name,job_id,salary
FROM employees
WHERE salary = (
SELECT MIN(salary)
FROM employees
)

/*
子查询编写技巧

1.从里往外写

2.从外往里写


*/

# 习题：查询与141号员工的manager-id
和department-id相同的其他的员工的employee_id,manager_id,department_id

# 方式一：

SELECT employee_id,manager_id,department_id
FROM employees
WHERE manager_id =(
SELECT manager_id
FROM employees
WHERE employee_id = 141
)
AND department_id = (
SELECT department_id
FROM employees
WHERE employee_id = 141
)
AND employee_id != 141;

#方式二：

SELECT employee_id,manager_id,department_id
FROM employees
WHERE (manager_id,department_id) = (
SELECT manager_id,department_id
FROM employees
WHERE employee_id = 141
)
AND employee_id != 141;

# 习题：查询最低工资大于110号部门最低工资的部门id和其最低工资

SELECT department_id,MIN(salary)
FROM employees
GROUP BY department_id
HAVING MIN(salary) > (
SELECT MIN(salary)
FROM employees
WHERE department_id = 110
);

#去空格

SELECT department_id,MIN(salary)
FROM employees
GROUP BY department_id
HAVING MIN(salary) > (
SELECT MIN(salary)
FROM employees
WHERE department_id = 60
)

SELECT department_id,MIN(salary)
FROM employees
GROUP BY department_id
HAVING MIN(salary) > (
SELECT MIN(salary)
FROM employees
WHERE department_id = 60
)
AND department_id IS NOT NULL;

SELECT department_id,MIN(salary)
FROM employees
WHERE department_id IS NOT NULL
GROUP BY department_id
HAVING MIN(salary) > (
SELECT MIN(salary)
FROM employees
WHERE department_id = 60
)

# 语法错误
SELECT department_id,MIN(salary)
FROM employees
GROUP BY department_id IS NOT NULL
HAVING MIN(salary) > (
SELECT MIN(salary)
FROM employees
WHERE department_id = 60
)

# 非法使用子查询

SELECT employee_id,last_name
FROM employees
WHERE salary = (
SELECT MIN(salary)
FROM employees
GROUP BY department_id;
)

# 查询的是准缺的数