15. A computer storage medium including computer executable code for tuning a database query, comprising: computer executable code for allowing a user to select a query of a database; computer executable code for parsing the selected database query to determine that the database query includes a first operator; computer executable code for selecting an optimization mode from a plurality of available optimization modes, wherein: a first optimization mode is automatically selected if one or more statistics exist for a table identified by the database query, and a second optimization mode is selected if one or more statistics do not exist for the table identified by the database query; computer executable code for automatically tuning the selected database query based on the structure of the database and the selected optimization mode; and computer executable code for displaying the tuned database query, and wherein the computer executable code for automatically tuning the selected database query comprises computer executable code for automatically rewriting the selected database query by converting the first operator to a second operator.
15. A computer storage medium including computer executable code for tuning a database query, comprising: computer executable code for allowing a user to select a query of a database; computer executable code for parsing the selected database query to determine that the database query includes a first operator; computer executable code for selecting an optimization mode from a plurality of available optimization modes, wherein: a first optimization mode is automatically selected if one or more statistics exist for a table identified by the database query, and a second optimization mode is selected if one or more statistics do not exist for the table identified by the database query; computer executable code for automatically tuning the selected database query based on the structure of the database and the selected optimization mode; and computer executable code for displaying the tuned database query, and wherein the computer executable code for automatically tuning the selected database query comprises computer executable code for automatically rewriting the selected database query by converting the first operator to a second operator. 17. The computer storage medium as recited in claim 15 , wherein the plurality of available optimization modes include Cost based and Rule based modes.