user vanarkel said:
Check if a value is unique in columns of multiple sheets (removing duplicate email addresses)
I have spreadsheet which I use to administrate my members. This spreadsheet contains multiple member categories, for each member category I have a separate sheet in which I edit them. I want to keep these categories in different sheets, because editing everything from a single sheet will become to messy.In each sheets there is one column called email, now I want to know if the email addresses are duplicated in this sheet or in other sheets.