1. A method for generating a query plan for estimating a number of unique entry counts of an attribute in a database, said method comprising: identifying a sample of entries in the database; calculating a skewness of the entries in the sample; identifying at least one of a sampling percent and a coefficient of variance of the entries in the sample; selecting at least one of a plurality of estimators based upon the calculated skewness of the entries and at least one of the sampling percent and the coefficient of variance of the entries in the sample; and generating a query plan from the selected at least one of the plurality of estimators, wherein the query plan is operable to be implemented in estimating the number of unique entry counts of the attribute.