Which function is useful to remove duplicate data in given database in excel?

This is a very vague question. First of all there is a function known as remove duplicates. This will remove all duplicates in a given selection of data. However you will have see its relevance to your sheet. This is useful if there is only one column of data. However in case of mulitple columns, other options such as concentate would help.

conditional formatting

Remove Duplicate function

Remove duplicates (formatting)