我在制作高级（对我而言）查询时遇到问题。
我正在尝试获取名字，姓氏，职位，部门名称以及经理的名字和姓氏。如果由于某种原因你需要知道我在PHP中使用这个SQL。我限制为10，因为数据库是巨大的。我只需要为员工输入最新数据。由于工作促销等原因，他们有多个条目。
我包含了我认为您需要了解我的问题所需的一切。谢谢，如果你能提供帮助。
mysql>
SELECT DISTINCT employees.first_name, employees.last_name,
titles.title, departments.dept_name, z.first, z.last
FROM employees, dept_emp, departments, titles,
(
SELECT employees.first_name AS first, employees.last_name AS last
FROM employees, dept_emp, dept_manager
WHERE
employees.emp_no = dept_emp.emp_no
AND dept_manager.emp_no = dept_emp.emp_no
) AS z
WHERE
employees.emp_no = dept_emp.emp_no
AND dept_emp.dept_no = departments.dept_no
AND titles.emp_no = employees.emp_no
LIMIT 10;
+------------+-----------+-----------------+-------------+-----------+--------------+
| first_name | last_name | title | dept_name | first | last |
+------------+-----------+-----------------+-------------+-----------+--------------+
| Georgi | Facello | Senior Engineer | Development | Margareta | Markovitch |
| Georgi | Facello | Senior Engineer | Development | Vishwani | Minakawa |
| Georgi | Facello | Senior Engineer | Development | Ebru | Alpin |
| Georgi | Facello | Senior Engineer | Development | Isamu | Legleitner |
| Georgi | Facello | Senior Engineer | Development | Shirish | Ossenbruggen |
| Georgi | Facello | Senior Engineer | Development | Karsten | Sigstam |
| Georgi | Facello | Senior Engineer | Development | Krassimir | Wegerle |
| Georgi | Facello | Senior Engineer | Development | Rosine | Cools |
| Georgi | Facello | Senior Engineer | Development | Shem | Kieras |
| Georgi | Facello | Senior Engineer | Development | Oscar | Ghazalie |
+------------+-----------+-----------------+-------------+-----------+--------------+
10 rows in set (0.00 sec)
数据库是mysql.com的员工数据库： http://dev.mysql.com/doc/index-other.html
mysql> desc departments;
+-----------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------+-------------+------+-----+---------+-------+
| dept_no | char(4) | NO | PRI | NULL | |
| dept_name | varchar(40) | NO | UNI | NULL | |
+-----------+-------------+------+-----+---------+-------+
2 rows in set (0.22 sec)
mysql> desc dept_emp;
+-----------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------+---------+------+-----+---------+-------+
| emp_no | int(11) | NO | PRI | NULL | |
| dept_no | char(4) | NO | PRI | NULL | |
| from_date | date | NO | | NULL | |
| to_date | date | NO | | NULL | |
+-----------+---------+------+-----+---------+-------+
4 rows in set (0.20 sec)
mysql> desc dept_manager;
+-----------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------+---------+------+-----+---------+-------+
| dept_no | char(4) | NO | PRI | NULL | |
| emp_no | int(11) | NO | PRI | NULL | |
| from_date | date | NO | | NULL | |
| to_date | date | NO | | NULL | |
+-----------+---------+------+-----+---------+-------+
4 rows in set (0.21 sec)
mysql> desc employees;
+------------+---------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+------------+---------------+------+-----+---------+-------+
| emp_no | int(11) | NO | PRI | NULL | |
| birth_date | date | NO | | NULL | |
| first_name | varchar(14) | NO | | NULL | |
| last_name | varchar(16) | NO | | NULL | |
| gender | enum('M','F') | NO | | NULL | |
| hire_date | date | NO | | NULL | |
+------------+---------------+------+-----+---------+-------+
6 rows in set (0.32 sec)
mysql> desc salaries;
+-----------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------+---------+------+-----+---------+-------+
| emp_no | int(11) | NO | PRI | NULL | |
| salary | int(11) | NO | | NULL | |
| from_date | date | NO | PRI | NULL | |
| to_date | date | NO | | NULL | |
+-----------+---------+------+-----+---------+-------+
4 rows in set (0.34 sec)
mysql> desc titles;
+-----------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------+-------------+------+-----+---------+-------+
| emp_no | int(11) | NO | PRI | NULL | |
| title | varchar(50) | NO | PRI | NULL | |
| from_date | date | NO | PRI | NULL | |
| to_date | date | YES | | NULL | |
+-----------+-------------+------+-----+---------+-------+
4 rows in set (0.60 sec)
答案 0 :(得分：1)
我正在尝试获取名字，姓氏，职位，部门名称以及经理的名字和姓氏
使用理论（但如果你有大表，它可能没有优化），一步一步地做。假设你有一个包含日期的$date PHP变量（比如date('Y-m-d 00:00:00')的结果），或者你可以使用MySQL的日期。
1 /获得员工身份：
SELECT
e.first_name,
e.last_name
FROM
employees AS e
WHERE
1
2 /添加他/她当前的标题
SELECT
e.first_name,
e.last_name,
t.title
FROM
employees AS e,
titles AS t
WHERE
e.emp_no=t.emp_no AND t.from_date<='$date' AND t.to_date>='$date'
3 /获取他/她当前的部门（来自dept_emp）并检索部门的名称
SELECT
e.first_name,
e.last_name, t.title,
d.dept_name
FROM
employees AS e,
titles AS t,
dept_emp AS de,
departments as d
WHERE
e.emp_no=t.emp_no AND t.from_date<='$date' AND t.to_date>='$date'
AND
e.emp_no=de.emp_no AND de.from_date<='$date' AND de.to_date>='$date'
AND
d.dept_no=de.dept_no
dept_manager）并检索他/她的名字（来自employees）
SELECT
e.first_name AS empFN,
e.last_name AS empLN,
t.title AS empT,
d.dept_name AS dept,
em.first_name AS manFN,
em.last_name AS manLN
FROM
employees AS e,
titles AS t,
dept_emp AS de,
departments as d,
dept_manager AS dm,
employees AS em
WHERE
e.emp_no=t.emp_no AND t.from_date<='$date' AND t.to_date>='$date'
AND
e.emp_no=de.emp_no AND de.from_date<='$date' AND de.to_date>='$date'
AND
d.dept_no=de.dept_no
AND
em.emp_no=dm.emp_no AND dm.from_date<='$date' AND dm.to_date>='$date'
AND
de.dept_no=dm.dept_no
在那里你可以追加一个LIMIT（和一个ORDER BY，你可能不知道在有限制的情况下会选择哪些结果），和/或添加{{1}您希望获得相关信息的员工WHERE。虽然没有经过测试，但它主要是为了让您了解如何构建请求。
这是理论，这个请求可能和你写的一样重要。由于您将SQL与PHP一起使用，因此最好只检索您感兴趣的主键，然后发送短请求以检索所需的信息。我的意思是这样的（使用虚假功能但精神在这里）：
emp_no希望这会有所帮助：）