Match and Replace a column with awk

Question

I need to replace the column 13 of file 2, with the column 2 of file 1, when column 1 of file 1 matches with col 2 of file 2.

file 1

AAAA00000687697 HPNMS
AAAA00000693037 GER112
AAAA00000349750 FRA0158

file 2

585     AAAA00000687697 1    +       11868   14409   14409   14409   3       11868,12612,13220,      12227,12721,14409,      0       BBBB00000223972 none    none    -1,-1,-1,
585     AAAA00000693037 1    +       11871   14412   14412   14412   3       11871,12612,13224,      12227,12721,14412,      0       BBBB00000223972 none    none    -1,-1,-1,
585     AAAA00000349750 1    +       11873   14409   14409   14409   4       11873,12594,13402,13660,        12227,12721,13655,14409,        0       BBBB00000223972 none    none    -1,-1,-1,-1,

Output should be like

585     AAAA00000687697 1    +       11868   14409   14409   14409   3       11868,12612,13220,      12227,12721,14409,      0       HPNMS           none    none    -1,-1,-1,
585     AAAA00000693037 1    +       11871   14412   14412   14412   3       11871,12612,13224,      12227,12721,14412,      0       GER112          none    none    -1,-1,-1,
585     AAAA00000349750 1    +       11873   14409   14409   14409   4       11873,12594,13402,13660,        12227,12721,13655,14409,        0       FRA0158 none    none    -1,-1,-1,-1,

I tried the codes below

 awk 'NR==FNR{a[$1]=$2;next} $2 in a {$13=a[$1];print}' FS='\t' OFS='\t' file1.txt file2.txt  > output.txt

It prints the file 2, with an empty $13 th column.

When I tried to print a[$1] alone, it prints an empty file; and when I remove the ;next part in first curly brackets it then can print only the a[$1]. I don't know why it has some troubles saving the array.

Answer 1

Just replace $13 with the array string a[$2] if available:

awk 'NR==FNR{a[$1]=$2;next}($2 in a){$13=a[$2]}1' file1 file2