How to check/prevent duplicate data entered into cells

[mmartinez13]

I am currently using Data Validation to confirm correct data is entered into cells. I would also like to check/prevent duplicate numbers in some of the same columns/cells.

Any suggestions on how I do this?

Thanks in advance for your help.

 

[scottylad2]

What type of validation and what layout do you currently have?

 

[T. Valko]

I am currently using Data Validation to confirm correct data is entered into cells. I would also like to check/prevent duplicate numbers in some of the same columns/cells.

Any suggestions on how I do this?

Thanks in advance for your help.

See this...

http://contextures.com/xlDataVal07.html#Unique

 

[mmartinez13]

I am just using a worksheet, at the moment.

I am wanting to confirm that I do not duplicate data in columns B and D.

 

[scottylad2]

Assuming your putting data into column A in the range A1:A10, and the data you want to avoid duplicating is in B1:C10. Highlight A1:A10 and open the data validation dialogue, Alt + D + L is the keyboard shortcut. in the dropdown select custom, type =Countif($B$1:$C$10,A1)<=1 then click ok. Now if you duplicate any of the items in the range B1:C10 you should get an error message pop up

 

[mmartinez13]

Scotty:

Works well, thank you.