Most efficient way to select record if a value has changed
What would be the most efficient way to select a record when one of the value has changed? 
Ex: 

I have an account history table like below where records are being created when the account change:

    Id  AcctNb Active Created
    8   123456 1      01/03/2012
    6   123456 0      01/01/2012


I like to find an efficient way to return the record where the active status has changed since the last entry.
Most efficient way to select record if a value has changed
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What would be the most efficient way to select a record when one of the value has changed? 
Ex: 

I have an account history table like below where records are being created when the account change:

    Id  AcctNb Active Created
    8   123456 1      01/03/2012
    6   123456 0      01/01/2012


I like to find an efficient way to return the record where the active status has changed since the last entry.