Cannot compare two fields

[webfrank]

Hi,
great plugin!

I was trying to compare two fields like this:

where processed > 1 AND in_bytes_sum > 0 AND "last_switched_max" > "first_switched_min"

I tried different permutations, with and without " but I receive this error:

2022-11-27 13:32:21 +0000 [error]: config error file="/fluentd/etc/fluent.conf" error_class=Fluent::ConfigError error="filter_where: failed to parse \"where\" value_stack:[#
<Fluent::FilterWhere::Parser::LogicalOpExp:0x00007fb817b2ab98 @left=
<Fluent::FilterWhere::Parser::NumberOpExp:0x00007fb817b219a8 @left=#
<Fluent::FilterWhere::Parser::IdentifierLiteral:0x00007fb817b224c0 @text=\"processed\">, @right=#
<Fluent::FilterWhere::Parser::NumberLiteral:0x00007fb817b21c00 @text=\"1\", @val=1.0>, @operator=:GT>, @right=#
<Fluent::FilterWhere::Parser::NumberOpExp:0x00007fb817b24a40 @left=#
<Fluent::FilterWhere::Parser::IdentifierLiteral:0x00007fb817b20850 @text=\"in_bytes_sum\">, @right=#
<Fluent::FilterWhere::Parser::NumberLiteral:0x00007fb817b25058 @text=\"0\", @val=0.0>, @operator=:GT>, 
@operator=:AND>, \"AND\", #<Fluent::FilterWhere::Parser::IdentifierLiteral:0x00007fb817b2a698 
@text=\"last_switched_max\">, \">\"] error_value:#<Fluent::FilterWhere::Parser::IdentifierLiteral:0x00007fb817b29f18 
@text=\"first_switched_min\">"