I think it can probably be a lot simpler than what you've currently got. And the simpler it is, the easier it is to debug and maintain.

# read required ids into an array
my @reqids = <REQIDS_FILE>;
chomp @reqids;

# build regex containing all required ids
my $re = join '|', map { "\Q$_\E" } @reqids;
$re = qr/$re/;

# Process infile a line at a time looking for matches
while (<INFILE>) {
  if (/$re/) {
    print "Matched - $_";

    if (/SELECT/) {
      for (1 .. 3) {
        print scalar <IN_FILE>;
      }
    }
  }
}
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