Possible Duplicate:
T-SQL Cast versus Convert
What is the differences between Cast and Convert functions in SQL Server with T-SQL?
Possible Duplicate:
T-SQL Cast versus Convert
What is the differences between Cast and Convert functions in SQL Server with T-SQL?
Convert is a SQL server only function and Cast is more generic(can be used in other dbms). Convert provides more flexability than Cast. So if you are trying to choose which one to use, I would suggest Cast uness you have a specific reason to use Convert. As a suggestion;
Dates, times : Convert
Decimals, numerics : Cast