Mysql中類型轉換函數Cast()的用法

Cast(字段名 as 轉換的類型)，其中類型可以為：

BINARY[(N)]
CHAR[(N)]
DATE
DATETIME
DECIMAL[(M[,D])]
SIGNED [INTEGER]
TIME
UNSIGNED [INTEGER]

用法:

SELECT CAST(ctime AS char) as new FROM user;

ctime是原列名, new是新列名

參考:

https://stackoverflow.com/questions/12126991/cast-from-varchar-to-int-mysql