How I get SQL ISO8601(SQL 126) DateTime Format

 SQL 126  | yyyy-mm-ddThh:mi:ss.mmm | ISO8601 DateTime Format

Declare @ADate Date,

            @ATime Time

Select @ADate='2021-07-12', @ATime='9:05 AM'

Select @ADate AS ADate, @ATime AS ATime

SELECT CONVERT(VARCHAR, CAST(CONVERT(Varchar(15), @ADate, 112) + ' ' + CONVERT(Varchar(8), @ATime) AS DATETIME), 126) AS [SQL ISO8601 DateTime Format]