How can I calculate the total hours worked in a week from a MySQL table with time values?

Calculating Time Differences in MySQL

You have a MySQL table with date-time values in a specific format and would like to calculate the difference between them, then sum the results to obtain the total hours for a given period. Let's explore how to achieve this.

Using TIME_TO_SEC() and SEC_TO_TIME()

The TIME_TO_SEC() function converts a time value in the format "HH:MM:SS" to the number of seconds it represents. To calculate the difference between two time values, the following formula can be used:

TIME_DIFFERENCE = TIME_TO_SEC(END_TIME) - TIME_TO_SEC(START_TIME)

However, since the desired output is in hours, we need to convert the time difference from seconds to hours. This can be done using the SEC_TO_TIME() function:

TOTAL_HOURS = SEC_TO_TIME(TIME_DIFFERENCE)

Calculating the Total Hours

To find the total hours for a given period, such as a week, the following query can be used:

SELECT SEC_TO_TIME( SUM( TIME_TO_SEC( `time` ) ) ) AS total_time
FROM time_table;

In this query, the TIME_TO_SEC() function is applied to each time value in the time column. The results are then summed using the SUM() function. Finally, the SEC_TO_TIME() function is used to convert the total seconds to hours, providing the desired output.

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