There is a table with 57M records. There is a date field and there are 50 distinct date values there. (so approx 1.13M/each date average)
there is a query that does a SELECT from this table with the only condition on the date field.
SELECT 6 columns from table where field = '2011-09-30'
will a non clustered key recommended on that field? will it help, since there are so many records and only so few dates on which the WHERE condition is based in the SELECT query?