data import and decimal separator interpretation

Hello

I have some tables under .txt format I am trying to import through data > new query > from file > from folder. The decimal separator is ".", but after I combine the tables the separator is interpreted as ",", and my values become messed. Because my default decimal separator is already defaulted to ".", I don't know what is the problem. Here are two screenshots of the problem.

The first picture is the correct one, and the second is the problem.