Get the character between first 2 special character in SQL

Question

I have data in sql (Just to note: SQL STudio is the IDE) like:

data
a_10_b_c
a_1_b_c

I want to get t

Answer 1

You can do this with nested string functions. Often, this is simpler using outer apply:

select t3.output
from t outer apply
     (select stuff(t.col, 1, charindex('_', t.col), '') as col2
     ) t2 outer apply
     (select left(t2.col2, charindex('_', t2.col2)) as output
     ) t3;