It acts similiarly to Excel's VLOOKUP function with some extra arguments. It takes the value that you want to take from another table and returns the corresponding value from another table. Basically it's an SQL Left Join.
Usage
VLOOKUP(
lookup_from_table,
lookup_column_value = "Name of the column to lookup",
lookup_where_table,
lookup_where_table_column = "Name of the column to compare",
return_which_column = "Name of the column to return"
)
Arguments
lookup_from_table
The table it should lookup values from
lookup_column_value
which column should be looked up
lookup_where_table
which table should it look for the values in
lookup_where_table_column
Which column should it look for the values in.
return_which_column
Which column should it return
Value
In this case we have built-in database Sales and Street. We try to merge these 2 tables to see on which street are the salesman based on their countries. Function can return numeric,character,logical or any other class, it depends on what is in the table you are looking up the value in.