• Hope this should work.

    DECLARE @a varchar(20) = 'INV CRT IS15000467 1'

    DECLARE @b-2 varchar(20) = 'INV CSH IS15000442 10'

    select substring(stuff(@a, 1,Charindex(' ',@a, Charindex(' ',@a,0)+1),''),0, Charindex(' ', stuff(@a, 1,Charindex(' ',@a, Charindex(' ',@a,0)+1),'')))

    select substring(stuff(@b, 1,Charindex(' ',@b, Charindex(' ',@b,0)+1),''),0, Charindex(' ', stuff(@b, 1,Charindex(' ',@a, Charindex(' ',@b,0)+1),'')))