在SQL SERVER中,cast和convert函式都可用於型別轉換,其功能是相同的,

只是語法不同.

cast一般更容易使用,convert的優點是可以格式化日期和數值.

程式碼

select CAST("123" as int) -- 123

select CONVERT(int, "123") -- 123

select CAST(123.4 as int) -- 123

select 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) -- 123

select CONVERT(decimal, "123.4") -- 123

select CAST("123.4" as decimal(9,2)) -- 123.40

select CONVERT(decimal(9,2), "123.4") -- 123.40

declare @Num money

set @Num = 1234.56

select CONVERT(varchar(20), @Num, 0) -- 1234.56

select CONVERT(varchar(20), @Num, 1) -- 1,234.56

select CONVERT(varchar(20), @Num, 2) -- 1234.5600