I am in the learning phase of google spreadsheet. I am trying to get the date corresponding to the company name if the company name is duplicated.

Public google sheet

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  The closest I could get is using FILTER:

  =IFERROR(INDEX(FILTER($B$2:$B2;$A$2:$A2=$A3);COUNTA(FILTER($B$2:$B2;$A$2:$A2=$A3)));"")
  

  Place this in the second row of your data (the 3rd row of your table if you have headers), because it will not work for the first row. Then, you drag this formula down for all your rows.

  Note:

  • A2 is where I had the first company, like "Apple"
  • B2 is where I had the first date, like "Jan 1"

  You can place this formula in C3, and drag-copy to all rows beneath it using the colored square in the bottom-right corner of the cell you have highlighted.

  

  (In case you didn't know)

  Have fun! ^_^