Why does my BETWEEN predicate not match any rows? [closed]

I got this table list:

table pinjam

kd_pinjam(primary) |  norek        | tgl_pinjam | jml_angsuran | jml_pinjam | sisa 
pin-0001           | 7811088313831 | 2020-12-20 | 10           | 5000000    | 10

table riwayat_pinjam

kd_pinjam(primary) | norek         | jml_pinjam | angsuran | gagal_bayar | tgl_lunas 
pin-0001           | 7811088313831 | 5000000    | 10       | 0           | null

I want to create a monthly report, for customers that have loan in a certain month (ex: January)

This is syntax that I use:

SELECT sum(pinjam.jml_pinjam) as pinjam 
from pinjam 
left join riwayat_pinjam 
  on pinjam.kd_pinjam = riwayat_pinjam.kd_pinjam 
where month(tgl_pinjam) BETWEEN month('2020-12-01') and month('2021-02-28')

But the result I get is that pinjam is null. I expect pinjam to equal 5000000.

What is wrong with my query?

x BETWEEN a AND b translates to x >= a AND x <= b. In your case a is 12 and b is 2; there is nothing that is simultaneously greater than 12 and less than 2, so no rows match.

This will avoid most issues:

where tgl_pinjam >= '2020-12-01'
  AND tgl_pinjam  < '2020-12-01' + INTERVAL 3 MONTH

Even without worrying about leap year.