How to concatenate a datetime value with time and milliseconds

[PaigeMiller]

That looks good, but since I don't know what is in your data sets (what variable names, and what variable types numeric or character, and what the variable values) it still might have problems. Which is why I suggested you provide a portion of data sets one and two via these instructions, and then we can all stop guessing.

[Tom]

A time value is already a number of seconds, so no need for all of those extra function calls.

datetime=dhms(date,0,0,time);

[Kurt_Bremser]

In the enhanced editor settings, make sure that tabs are replaced with blanks.

[Tom]

Never put tab characters in program files.