Concatenate text and convert to numbers in Excel

I have a long Excel file which keep the date, month, year, hour, minute, and second in separate columns (figure 1). I want to use only one column to present the time, so it would be easier to plot the time as x-axis. Here is the function I used in cell G2:

=VALUE(CONCATENATE(A2,"/",B2,"/",C2," ",D2,":",E2,":", F2))

The Value function convert the text into numbers.
The Concatenate function connects all the text and convert them into one string.

How to concatenate two datasets in Matlab?

I wanted to vertically combine two datasets, so I can keep a long file of all the test results. The join function does not work here anymore. Of course this is even not a problem in Excel. However, to make it work in Matlab, it did took me a while to figure it out.

c=cat(1, a, b)