Its a 'literal' search
Your original Vlookup query had you with
*0026 as a lookup value, which is taken as a wildcard search due to the *
Now if you had a table with
Sheet1
<colgroup><col style="font-weight:bold; width:30px; "><col style="width:64px;"><col style="width:64px;"></colgroup><tbody>
[TD="bgcolor: #cacaca, align: center"]1[/TD]
[TD="align: right"]90026[/TD]
[TD="align: right"]1[/TD]
[TD="bgcolor: #cacaca, align: center"]2[/TD]
[TD="align: right"]2[/TD]
</tbody>
Excel tables to the web >> Excel Jeanie HTML 4
And you were searching for *0026 using a vlookup as =Vlookup("*0026", A1:B2,2,0) you would get a 1, as 90026 meets the criteria, that is *0026 is saying go look for anything that ends with 0026, it ignores the leading values, if you had *002*, it would search for 002 and ignore the leading and trailing characters
The Tilde (~) is used as a literal, now with the previous we were looking for a *0026, but excel did not see this so we had to tell it we really wanted it, so we use a Tilde (~), so if we had *0026 in C1, we would put ="~"&C1 which stops the * from being a wildcard so we are really search for *0026
Hope that helps