检查工作表（多张工作表）中是否存在值并返回“条目已存在”-Excel

Question

I have an excel file with multiple sheets with row entries, where each entry has multiple columns with different information. What I want to do is, every time I enter a new entry, check if it already exists in another sheet (of the same file). That is to check if a row in the file contains the same information and have a return like "Entry already exists" or FALSE or anything to let me know so that I don't have the same entry twice in the file.

I have no idea how to even begin (or even if that is possible). Can anyone help?

ps. Sorry if my question is too complicated, I couldn't find a better way to put it into words.

Answer 1

If your data is in one column or one row, by faaar the easiest method is to use conditional formatting; Conditional Formatting -> Highlight cells rules -> Duplicate values.

If you want to check across different sheets or different columns, use MATCH function. MATCH returns the relative location of a string in an array. I'd see it working something like...

=MATCH(NewEntry,ArrayWhereItCouldAppear,0)

If you put in entry "x" in row, let's say, 102 (eg address is "B102"), but you already have entry "x" in row 15 (eg address is "B15"), then MATCH would be returning "15".

In order to automatize it, you'd need to OFFSET to provide the last row's reference (I assume you are adding new rows). Use something like...

=OFFSET(B1, COUNTA(B:B)-1, 0)

as your NewEntry. Offset in essence "moves" your range based on the criteria; the above instructs it to return whatever is found in COUNTA(B:B)-1 rows under the cell B1. COUNTA counts non-empty cells, and the -1 accounts for the (likely) header of your table. Thus, if you were adding "x" in row 102, the function would return your "x".

Lastly, you have mentioned you would like to see TRUE or FALSE appear. The easiest check is to do a boolean check if MATCH returns anything greater than zero. However, MATCH won't return zero if it doesn't find an entry; it will return an error. Therefore, we need to wrap our formula in IFERROR. We thus end with something like...

=IFERROR(MATCH(OFFSET(ColumnWhereUniqueIDIs:1,COUNTA(ColumnWhereUniqueIDIs:ColumnWhereUniqueIDIs)-1,0),ArrayWhereItCouldAppear,0),0)>0

This is cool, because you can plug in ANY array where the "x" might appear. You can do this across multiple sheets (simply adding the formulas, as in "check this array" + "check this array" + ...).

I hope this helps. If anyone can come up with an easier solution, please do!