However, I am getting warning message as all formats failed to parse and there are no values shown in the table as well. It would be helpful for me if someone can suggest any ideas.
Could you please turn this into a self-contained reprex (short for reproducible example)? It will help us help you if we can be sure we're all working with/looking at the same stuff.
If you run into problems with access to your clipboard, you can specify an outfile for the reprex, and then copy and paste the contents into the forum.
Did you try copying and pasting exactly what I posted? It’s using backticks, which is a different character from both single and double quote marks. Unfortunately, some non-English keyboard layouts make it very difficult to type a backtick. On a typical US QWERTY keyboard layout it’s to the left of the 1 key. Here is where it’s found on a few other layouts.
R uses both single and double quote marks to identify character strings. R allows you to use backticks to enclose otherwise invalid names (such as Order Date, which can’t be used on its own because it has a space in it).