Get the numeric from string in SQL

declare @st varchar(50) ='Mahesh999666777555'

select PatIndex('%[0-9]%',@st)

select substring(@st,PATINDEX('%[0-9]%', @st),len(@st)) GetNumber

FiscalQuarter + YearQuarter

ALTER FUNCTION [dbo].[GetFiscalQuarters] ( @Asofpdate    DATETIME )
RETURNS varchar(10)
BEGIN

    DECLARE @vOutputDate        varchar(10)

    SET @vOutputDate =  Convert(varchar(max),
(case when DATEPART(M,@Asofpdate) between 5 and 7 then 1 when DATEPART(M,@Asofpdate) between 8 and 10 then 2
when DATEPART(M,@Asofpdate) between 11 and 1 then 3 when DATEPART(M,@Asofpdate) between 2 and 4 then 4
end) ) + CONVERT(varchar(max), Year(@Asofpdate))
   RETURN @vOutputDate

END


ALTER FUNCTION [dbo].[GetYearQuarters] ( @Asofpdate    DATETIME )
RETURNS varchar(10)
BEGIN

    DECLARE @vOutputDate        varchar(10)

    SET @vOutputDate =  Convert(varchar,DATEPART(QUARTER,@Asofpdate)) + CONVERT(varchar, Year(@Asofpdate))
   RETURN @vOutputDate

END