mysql select后面的子查询

标签：employee   nts   sel   pre   str   sele   art   使用   部门   

#案例：查询每个部门的员工个数

SELECT d.*,(
    SELECT COUNT(*)
    FROM employees
    WHERE employees.`department_id`=d.department_id
)
FROM
    departments d;

#案例：查询员工号=102的部门名

SELECT department_name
FROM
    employees e
INNER JOIN
    departments d
ON
    e.`department_id`=d.`department_id`
WHERE
    e.`employee_id`=102;

用子查询

SELECT (

SELECT department_name
FROM
    employees e
INNER JOIN
    departments d
ON
    e.`department_id`=d.`department_id`
WHERE
    e.`employee_id`=102
);

mysql select后面的子查询

标签：employee   nts   sel   pre   str   sele   art   使用   部门   

原文地址：https://blog.51cto.com/14437184/2438373