AVG(expression) : Returns average value of expression CORR(expression1, expression2) : Returns the coefficient of correlation of a set of number pairs COVAR_POP(expression1, expression2) : Returns the population covariance of a set of number pairs COVAR_SAMP(expression1, expression2) : Returns the sample covariance of a set of number pairs COUNT(expression) : Returns the number of rows returned by the query
dig is one of the finest dns tools for unix and linux admins. ISC (Internet Systems Consortium) provides windows binary for the dig tool. In order to use it from windows machine, download bind zip file from http://www.isc.org downloads site. Then extract following files to your local folder that is already in your %PATH% environment variable or create a folder in the program files folder and add it to the %PATH% environment variable so you can use it from command line without writing the full path.