Вставить пробел перед заглавной буквой

DECLARE @s VARCHAR(100) = 'ИвановИванИванович'
 
SELECT CASE WHEN ASCII(s) = ASCII(UPPER(s)) AND NUMBER > 1 THEN ' ' ELSE '' END + s
FROM(
    SELECT SUBSTRING(@s,NUMBER,1)s, NUMBER
    FROM master..spt_values
    WHERE TYPE = 'P' AND NUMBER BETWEEN 1 AND LEN(@s)
)t
ORDER BY NUMBER
FOR xml path('')

DECLARE @name nvarchar(128) ='ПетровПетрПетрович'
DECLARE @sProbelom nvarchar(128) = ''
;WITH Bukwy(id, bukwa, hwost) AS
(
SELECT 0, LEFT(@name, 1), RIGHT(@name, LEN(@name)-1)
UNION ALL
SELECT id+2, LEFT(hwost, 1), RIGHT(hwost, LEN(hwost)-1) FROM Bukwy WHERE LEN(hwost)>0
)
, Probely(id, bukwa) AS
(
SELECT id, bukwa FROM Bukwy
UNION ALL SELECT id-1, ' ' FROM Bukwy 
WHERE ASCII(bukwa) = ASCII(UPPER(bukwa))
AND id > 0
)
SELECT @sProbelom = @sProbelom + bukwa FROM Probely ORDER BY id
SELECT @sProbelom

ALTER FUNCTION dbo.StringWithSpace (@string nvarchar(MAX))
RETURNS NVARCHAR(MAX)
AS
BEGIN
    DECLARE @len INT = LEN(@string)
           ,@iterator INT = 2;
    WHILE @iterator <= LEN(@string)
    BEGIN
        IF PATINDEX('[АБВГДЕЖЗИКЛМНОПРСТУФХЦЧЩШ]',SUBSTRING(@string,@iterator,1) COLLATE Latin1_General_CS_AI) <> 0
        BEGIN
            SET @string = STUFF(@string,@iterator,0,' ');
            SET @iterator += 1;
        END;
        SET @iterator += 1;
    END
    RETURN @string;
END;

DECLARE @t TABLE (id INT, FIO nvarchar(MAX))
INSERT @t SELECT 1, 'ИвановИванИванович'
INSERT @t SELECT 2, 'ПетровПетрПетрович'
INSERT @t SELECT 3, 'Сидоров'
SELECT id, dbo.StringWithSpace(Fio) FROM @t