如何在MySql SELECT语句中正确使用CAST函数？

I'm converting an MSSQL DB to MySQL DB and I have a stored procedure that is using a cast function to convert from a datetime datatype to a varchar datatype. Whether or not this matters in php/mysql since php isn't strongly typed (and I dont know if it would matter or not) I really want to keep the SP a close to the orginal as possible so I can maintain the same expected functionality. The problem is that I can't get the cast function to work right in mysql. Here is a test I tried that got me an error:I'm converting an MSSQL DB to MySQL DB and I ha