CAST and CONVERT have similar functionality. CONVERT is specific to SQL Server, and allows for a greater breadth of flexibility when converting between date and time values, fractional numbers, and monetary signifiers. CAST is the more ANSI-standard of the two functions. Check this blog for examples of using both of those: http://sqltutorials.blogspot.com/2007/06/sql-cast-and-convert.html
原文：http://www.cnblogs.com/willwxw/p/5166204.html