• An alternative (simply a refactor):

    DECLARE @v-2 VARCHAR(1000)

    SET @v-2 = '2,22,5,1,88,2000,7897,800'

    SELECT CAST( x.query('fn:min(number)') AS varchar),

    CAST( x.query('fn:max(number)') AS varchar),

    CAST( x.query('fn:count(number)') AS varchar)

    FROM

    (

    SELECT CAST('<number>' + REPLACE(@v,',','</number><number>') + '</number>' AS XML) AS X

    ) s