关于php：使用时间戳计算员工的工作时间

Calculating working hours of employees using time stamps

我在数据库中有四列，其中包括员工姓名、日期和时间的时间戳，它们显示了员工的进出时间。超时在进入后进入下一行，每个员工一天进出很多次，但是我必须考虑每个员工的第一次和最后一次，并找出时间之间的差异计算每个员工的总工作时间。数据库如下所示。谁能帮我解决这个问题

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E Name Turnstile In Turnstile Out Combine
Abhijit K T SP Turnstile 03 In 2015-01-01 08:08:36
Abhijit K T SP Turnstile 03 In 2015-01-02 08:33:52
Abhijit K T SP Turnstile 01 Out 2015-01-01 18:22:44
Abhijit K T SP Turnstile 03 In 2015-01-01 18:23:00
Abhijit K T SP Turnstile 01 Out 2015-01-02 19:17:08
Abhilash S M SE Turnstile 01 Out 2015-01-02 12:08:08
Abhilash S M SE Turnstile 01 In 2015-01-02 12:13:20
Abhilash S M SE Turnstile 01 Out 2015-01-02 13:07:20
Abhilash S M SE Turnstile 02 In 2015-01-02 13:13:32
Abhilash S M SE Turnstile 01 Out 2015-01-02 13:13:24
Abhilash S M SE Turnstile 03 Out 2015-01-02 14:44:44
Abhilash S M SE Turnstile 01 In 2015-01-02 14:50:16
Abhilash S M SE Turnstile 01 Out 2015-01-02 16:32:24
Abhilash S M SE Turnstile 01 In 2015-01-02 16:37:28
Abhilash S M SP Turnstile 03 In 2015-01-02 08:33:32
Abhilash S M SE Turnstile 01 Out 2015-01-02 18:20:20
Abhilash S M SE Turnstile 01 In 2015-01-02 18:20:28
Abhilash S M SP Turnstile 03 In 2015-01-02 18:25:44
Abhilash S M SP Turnstile 03 Out 2015-01-02 18:28:24
Abhilash S M SP Turnstile 03 In 2015-01-01 10:27:40
Abhilash S M SE Turnstile 01 Out 2015-01-01 12:21:56