DECLARE @String VARCHAR(300);

SET @String =

'here is my phone number 1234567890. but my cell is 4444444444, ' +

'and my work number is 5555555555. i said my my phone number 1234567890. ' +

'and my cell is 4444444444, and my work number is 5555555555.';

WITH Numbers (n)

AS (

-- Numbers 1...length of string

SELECT TOP (DATALENGTH(@String))

ROW_NUMBER() OVER(

ORDER BY (SELECT 0))

FROM master.sys.columns C1,

master.sys.columns C2,

master.sys.columns C3

)

SELECT @String = STUFF(@String, N.n + 4, 6, REPLICATE('X', 6))

FROM Numbers N

WHERE SUBSTRING(@String, N.n, 10) LIKE '4444[0-9][0-9][0-9][0-9][0-9][0-9]'

OR SUBSTRING(@String, N.n, 10) LIKE '1234[0-9][0-9][0-9][0-9][0-9][0-9]';

SELECT @String;