Google Sheets - Prevent Duplicate Entries 

Awesome video! Super helpful. This video could be slightly expanded to enforce uniqueness on a combination of columns. For example this validation on A6 and B6 would enforce that the combination of Item # and Item Name for a given row isn't duplicated: =(COUNTIF(ARRAYFORMULA(A$6:A&B$6:B),A6&B6)=1). I couldn't find anything on the interwebs that gave this tip.

Very helpful, thank you. How can this be applied across multiple sheets? For example, I have 'xy' allocated in sheet 1 so I would like to prevent the user from allocating that value in sheet 2, sheet 3 etc

Thanks for the great tutorial. What if we wanted to exclude any multiple dashes that occur in the range? How would you write that logic? Thx

Hi, I'd like to ask something: if we have a column with numbers only (e.g. customer phone numbers) and we want while we are entering a new number in this column, a warning message to appear, warning me that this number already exists, and if possible, to show me where (i.e., in which cell) this number is... is this possible in google sheets? And if yes, how can I do that? By means of what function? Thanks in advance.

Thank you, badly needed this

Thanks! This helped a lot - somehow its hard to find in google.......

Very useful tricks. Thanks for share. (Supper helpful). Your explain clearly.

What if I have a couple of columns to apply the data validation condition. It would be with countifs?

This was really great. I have a question (Google Sheets) if you would be so kind to help me. I have 4 cells (not in a range; they are independent cells) on a row that can only have the numbers 1, 2, 3 or 4 but with each of these numbers only showing once. How can I do that?

How to put a color for desame number are duplicate

How i can hight light duplicate values in deferent sheets? Thank you

how can i apply this to all cells in "A" , so that if i enter any duplicated value , it will stop me from inputting. Any solution ?

Hi Mate, This is great. What about if you add a new row within that range, will it pick that new row up within the column? Is there a way to make this work for all data and potential data in that particular column? Many thanks,

Exactly What I was looking for!!! Thank you so much!!

This is a great explanation of your solution, thank you very much!

Thank you, it was very helpful!

Hey Profile Oaktree hope all is well, what if you don't want duplicate entries however, you would increase the quantity when one is received.

super helpful! Thanks!

Great video, thank you.

Hi Profile Oaktree, I have a question hoping you would be kind enough to help me. I am working on a CSV file right now with 300K+ columns, and I have noticed that there are duplicate entries for some columns. Fortunately, I have successfully removed them (that was exhausting *phew*), what I wanted to know now is that is it possible to use this formula when I am copy-pasting the entry and not inputting it? Thank you. :)

Hi its showing me This cell's contents violate its validation rule

how can I prevent duplicate text entries in google sheets, such as names? such as john Doe in line 3 and john Doe in line 20?

Thank you so much!!!

Very helpful! Tnank!

Great simple video thank you! Question, is there a way to check if the whole row is a duplicate rather than just one cell in the row? Example: =Countif(A6:E25, A6:E6)? to check the whole row of A? I use google forms for booking appointments/ customer orders, and it is submitting duplicated submissions to my google sheets. Can not necessarily narrow it down to just one cell of their submission (I do not use an Item# like you have above).

Very useful video. Thanks. How can I copy a range and paste it as a picture?

how to prevent duplicate entries on multiple sheets?

thanks for the video

how do create a Google form to enter the part numbers and prevents you from going forward if a duplicate entry is made or when the submit button is hit it doesn't record the response but produces an error message indicating a duplicate entry was done

Thanks! now is there a way to combine that + list of items

how to use this google form?

thanks

How we link with google form?

cool

Thank you so much!!