How well do you know your LOOKUPs? – Quiz Answers & Discussion

Last week, we had our very first quiz – “How well do you know your LOOKUPs?“. I hope you have enjoyed it.

Today lets understand the answers & explanations for this quiz.

First a summary of results (and controversies):

More than 3,200 people attempted the quiz.  Roughly 45% of you got correct answers. That said there were 4 questions where 90% of you made mistakes. This is mainly because these questions & answer choices were ambiguous. As this is the first time I ran a quiz on Chandoo.org, it was a learning experience for me too. I promise to keep the questions & answer choices clearer next time 🙂

*Questions that are ambiguous are marked with a * below.

Here are the answers & explanations this quiz.

If your lookup table is in ascending order, then you can omit 4th parameter and VLOOKUP will find either exact or approximate match.

We use 4th parameter as FALSE when our list may not be in any particular sort order and we are looking for exact matches.

So the answer is When my lookup list is not in any particular sort order

Related: Introduction to VLOOKUP – Syntax, explanation & examples

We can check whether a value is present in a list or not using any of below formulas.

COUNTIF / COUNTIFS

• COUNTIF(range, value you are looking) will be >0 if value is available.
• Introduction to COUNTIF formula

VLOOKUP

• VLOOKUP(value you are looking, range, 1,false) will not be an error if value is available

SUMPRODUCT

• SUMPRODUCT(–(range=value you are looking)) will be >0
• Introduction to SUMPRODUCT formula

MATCH

• MATCH(value you are looking, range,0) will not be an error
• Introduction to MATCH formula

VLOOKUP will always find the first match (assuming you specified FALSE in last parameter).

Related: Finding 2nd, 3rd matches using VLOOKUP.

We all want a world without traffic, crying babies & error messages. Alas, there are no Excel formulas for first 2, but we can suppress error messages for sure, by using any of below formulas:

• IFERROR
• ISERROR
• ISNA
• IFNA (new in Excel 2013)

Although VLOOKUP is very powerful, it has one limitation. It can only search in left most column and get values from columns to right. To lookup on a column in middle and get values from either left or right, we can use below alternatives.

INDEX + MATCH formulas

• =INDEX(invoiceIDs, MATCH(thisID, customerIDs, 0))
• More on this technique

OFFSET + MATCH formulas

• =OFFSET(invoiceIDs, MATCH(thisID, customerIDs, 0),0,1,1)
• More on this technique, OFFSET formula explained

VLOOKUP + CHOOSE formulas

• =VLOOKUP(thisID,CHOOSE({2,1},invoiceIDs, customerIDs), 2, FALSE)
• More on this technique

To find the last invoice and its amount, we need to few ingredients:

• Know how many invoices are there for given invoice number
• A helper column with invoice counts up to that point

For above data, you can insert a column between A&B and use it as helper column. Write this formula in it (and fill down)

=A1&”-“&COUNTIF($A$1:A1,A1)

This will tell us how many times each invoice number is repeated up to that point.

Now, use the VLOOKUP formula to find last invoice’s amount like this:

=VLOOKUP(this_invoice&”-“&COUNTIF(A1:A100, this_invoice), B1:C100, 2, false)

Related: Finding 2nd, 3rd … matches using VLOOKUP.

Nah, it will return #N/A error.

Do you know that you can use arrays for 3rd parameter in VLOOKUP? When you do it, you will get values from all column numbers mentioned in the array. So we get Joyce’s salary, special allowance, travel allowance and bonus amounts.

When wrapped in SUMPRODUCT, this will just be the sum of all these numbers.

Related: Extracting values from multiple columns using VLOOKUP.

To get the value from 2nd column, we write =VLOOKUP(value to lookup, A1:Z1000, 2, false)

To get 3rd column value, we need to replace 2 with 3.

What if we can write 1 formula and drag it side-ways so that 2 becomes 3,4…24,25?

Enter the COLUMNS() formula. It can be used to generate running numbers. So, our formula becomes,

=VLOOKUP(value to lookup, $A$1:$Z$1000, COLUMNS($A$1:A$1)+1, false)

now, you can just drag the VLOOKUP formula sideways and it will get you all the 25 values 🙂

Apart from COLUMNS(), you can also use ROWS(), COLUMN(), ROW() or simply a set of 25 numbers typed in a range and using cell references in place of 2,3,…24,25.

You can use any of below formulas to do this:

SUMIFS

=SUMIFS(amounts, customerIDs, this customer, invoiceIDs, this invocie)

SUMPRODUCT

=SUMPRODUCT(amounts, (customerIDs=this customer), (invoiceIDs=this invoice))

INDEX & MATCH

(Array formula)

{=INDEX(amounts, MATCH(this customer & this invoice, (customerIDs)&(invoiceIDs), 0)) }

Related: Various techniques for multi-condition lookups.

Want to master Lookup formulas?

Worry not. I am always looking out for you 🙂 Check out below pages for awesome resources, explanations & examples on Excel lookup formulas.

• Introduction to VLOOKUP formula – what is it & how to use it?
• Comprehensive guide to VLOOKUP & other lookup formulas
• VLOOKUP cheat sheet – download today

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