Q1 . Cluster Index scan will be used as "not in" clause exclude the values used from the all possible persontype values Q2. Index Seek will be used if table data are properly distributed across all the possible persontype else cluster Index scan will be used for huge number of rows .
first one will do full cluster scan not seek. but the second one will be seeking the SC value. first query will not let the index do the job automatically or based on its plan. the second one does.
Q1 . Cluster Index scan will be used as "not in" clause exclude the values used from the all possible persontype values
Q2. Index Seek will be used if table data are properly distributed across all the possible persontype else cluster Index scan will be used for huge number of rows .
first one will do full cluster scan not seek. but the second one will be seeking the SC value. first query will not let the index do the job automatically or based on its plan. the second one does.
Both will be clustered index scan only