If we have two fields: CustomerID and CustomerName in a table named tblcust of having 3 Lakh records.
we are indexing customer name to get result faster for query like: select * from tblcust where CustomerName like '%a%'
Can we index CustomerID to get result faster for query like: select * from tblcust where CustomerID = '3002'
I mean indexing is enough for any one field in a table or
we need to have index for two or more fields as per our wish ?
And Let me know what is the DisAdvantage of Index