VLOOKUP is a Microsoft Excel function that collects information from tables in which the first row contains the last names of individuals or identification numbers. VLOOKUP works by retrieving the data from a specified column in the rows of a table in which the data in the first column matches a particular value.
Any Excel table organized by unique identifiers in the first column of the table is a good candidate for use with the VLOOKUP function. For example, VLOOKUP can retrieve the first name, employee identification number or telephone number for a specific employee from a table of employees sorted by their last names in the first column. Another common use is to retrieve transaction information, such as the final price paid, date submitted or the part number involved with a specific invoice, by using a unique transaction number located in the first column of the table.
However, VLOOKUP has a number of limitations that are common to its use. The limitation most likely to cause issues when using the standard form of VLOOKUP is that the first column of the table that VLOOKUP queries must be sorted in ascending order, either alphabetically or numerically. If it is not, VLOOKUP may retrieve information from the wrong row. It is possible to specify that it match information exactly to avoid this issue, but this is not the default setting for the function.