如何使用T

https://data.stackexchange.com/stackoverflow/query/4803/so3087921

DECLARE @temp AS TABLE (hex char(6))INSERT  INTO @tempVALUES  ('3333CC') -- Should convert to Red: 51 Green: 51 Blue: 204DECLARE @table AS varchar(16)SET @table = '0123456789abcdef' -- Assuming case-insensitive collation!SELECt  hex       ,16 * (CHARINDEX(SUBSTRINg(hex, 1, 1), @table) - 1) + (CHARINDEX(SUBSTRINg(hex, 2, 1), @table) - 1) AS R       ,16 * (CHARINDEX(SUBSTRINg(hex, 3, 1), @table) - 1) + (CHARINDEX(SUBSTRINg(hex, 4, 1), @table) - 1) AS G       ,16 * (CHARINDEX(SUBSTRINg(hex, 5, 1), @table) - 1) + (CHARINDEX(SUBSTRINg(hex, 6, 1), @table) - 1) AS BFROM    @temp

https://dpatrickcaldwell.blogspot.com/2009/05/converting-hexadecimal-or-
binary-to.html中
有一个通用函数

我通常尽可能地避免使用标量函数，因为有可能诱使自己认为可以为500万行调用标量UDF，而不会对内联表达式造成任何损失。

您还可以使用内联表值UDF：

CREATE FUNCTION dbo.udf_HexToRGB (@hex char(6))RETURNS TABLEAS RETURN    (     SELECt 16 * (CHARINDEX(SUBSTRINg(@hex, 1, 1), '0123456789abcdef') - 1) + (CHARINDEX(SUBSTRINg(@hex, 2, 1), '0123456789abcdef') - 1) AS R,16 * (CHARINDEX(SUBSTRINg(@hex, 3, 1), '0123456789abcdef') - 1) + (CHARINDEX(SUBSTRINg(@hex, 4, 1), '0123456789abcdef') - 1) AS G,16 * (CHARINDEX(SUBSTRINg(@hex, 5, 1), '0123456789abcdef') - 1) + (CHARINDEX(SUBSTRINg(@hex, 6, 1), '0123456789abcdef') - 1) AS B    )GODECLARE @temp AS TABLE (hex char(6))INSERT  INTO @temp VALUES  ('3333CC') -- Should convert to Red: 51 Green: 51 Blue: 204SELECT  hex        ,R        ,G        ,B FROM    @tempOUTER APPLY dbo.udf_HexToRGB(hex)