SQL SERVER中强制类型转换cast和convert的区别

在SQL SERVER中,cast和convert函数都可用于类型转换,其功能是相同的,

只是语法不同.

cast一般更容易使用,convert的优点是可以格式化日期和数值.

代码如下：

select CAST('123' as int)   -- 123select CONVERT(int, '123')  -- 123select CAST(123.4 as int)   -- 123select CONVERT(int, 123.4)  -- 123 select CAST('123.4' as int)select CONVERT(int, '123.4')-- Conversion failed when converting the varchar value '123.4' to data type int.select CAST('123.4' as decimal)  -- 123select CONVERT(decimal, '123.4') -- 123 select CAST('123.4' as decimal(9,2))  -- 123.40select CONVERT(decimal(9,2), '123.4') -- 123.40declare @Num moneyset @Num = 1234.56select CONVERT(varchar(20), @Num, 0)  -- 1234.56select CONVERT(varchar(20), @Num, 1)  -- 1,234.56select CONVERT(varchar(20), @Num, 2)  -- 1234.5600