Extract row if both column values appear in a single column from a separate file

Question

I have two tab-separated files:

File 1

123   456
135   567
234   478

File 2

123    notimportant    notimportant2
456    notimportant    notimportant2
987    notimportant    notimportant2
135    notimportant    notimportant2
234    notimportant    notimportant2
478    notimportant    notimportant2

I need to extract lines from file1 if both entries in a single row are present in file2's first column. So the output file should be like:

Output

123   456
234   478

I previously used this awk command to extract rows if only the first column of file1 matched 1st column of file2

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

But I don't know how to expand it.

Answer 1

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

perl -lane '
   @ARGV and $h{$F[0]}++,next;
   print if @F == grep { $h{$_} } @F;
' file2 file1