How to Check if data from one column exists in another in Excel

This Video illustrates How to Check if data from one column exists in another in Excel.
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Search for value in column Excel
Check if value exists in list excel
Excel find values that exist in one column but not another
IF VLOOKUP
Find if Excel
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FIND in Excel
Lookup
How to check if one value exists in another column in Excel?
How do you check if one column value contains in another column?
How do you check if a value exists between two columns in Excel?
How to find data from one column in another column in Excel?