data:
code
A1
A2
A11
A22
A111
A222
A3333
A4444
We want to select a data set as follows.
A1
A2
A11
A22
A111
A222
Solution:
SELECT code
FROM data
WHERE code LIKE ‘A[0-9]’ — 1 digit
OR code LIKE ‘A[1-9][0-9]’ — 2 digits
OR code LIKE ‘A[1-9][0-9][0-9]’ — 3 digits
We can use len function as a filter
select * from data where code like ‘A[0-999]%’ and len(code)<=4