How to compare two columns with each cell in excel

Please follow the below link 

https://stackoverflow.com/questions/51770401/how-to-compare-two-cell-values-in-separate-columns-and-highlight-the-difference

Hi Krunal,

you need to open the Excel file and after comparison use the Range.Interior.Color property to change the background color of that cell to highlight it. Here is the code:

public void CompareExcelSheet(string excelFilePath)
{
	Application excelApp = new Application();
	Workbook workbook = excelApp.Workbooks.Open(excelFilePath);

	try
	{
		Worksheet worksheet = workbook.Sheets[1];

		for (int i = 1; i <= worksheet.UsedRange.Rows.Count; i++)
		{
			var columnAValue = worksheet.Cells[i, 1].Value;
			var columnBValue = worksheet.Cells[i, 2].Value;
			if (columnAValue != null && columnBValue != null)
			{
				if (!columnAValue.Equals(columnBValue))
				{
					// Change the background color of the unique value in column A to yellow
					worksheet.Cells[i, 1].Interior.Color = XlRgbColor.rgbYellow;

					// Change the background color of the unique value in column B to green
					worksheet.Cells[i, 2].Interior.Color = XlRgbColor.rgbGreen;
				}
			}
		}
	}
	catch (Exception ex)
	{

	}
	finally
	{
		workbook.Save();
		excelApp.Quit();
	}
}

//Method Calling:
CompareExcelSheet(@"YourPath\CompareTable.xls");

please refer below link, hope this will help

https://www.simplilearn.com/tutorials/excel-tutorial/compare-two-columns-in-excel#:~:text=Navigate%20to%20the%20%22Home%22%20option,matching%20values%20or%20unique%20values.