The advantage of this patch, is that I do not need to alias the sql_for_field method in my plugin!
I am also open for more elegant solution.
Thanks.
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Where is @$2@ from?
@field =~ /^(.+)\./@ returns only @$1@.
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For the below cases, With grouping of filters,

Suppose, If I add a custom filter through a plugin patch
<pre><code class="ruby">
add_available_filter("question.qassigned_to_id", :type => :list, :values => author_values,
:caption => :field_question_assigned_to_id, :name => l(:field_question_assigned_to_id_esi)
)
</code></pre>

The only way to handle the corresponding SQL query is to alias the sql_for_field.
Instead if the attached patch is provided,
I can avoid the alias and also have my method,

<pre><code class="ruby">
def sql_for_qassigned_to_id_field(.....)
.... sql logic...
end
</code></pre>

Thank You.
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In your attachment:sql_for_fields_with_group-git.diff

<pre><code class="ruby">
elsif field =~ /^(.+)\./ && respond_to?("sql_for_#{$2}_field")
# specific statement
filters_clauses << send("sql_for_#{$2}_field", field, operator, v)
</code></pre>

http://ruby-doc.org/core-2.1.1/Regexp.html#class-Regexp-label-Special+global+variables
> $1, $2 and so on contain text matching first, second, etc capture group;

But your @field =~ /^(.+)\./@ has only one parenthesis.
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Yes, Realized my mistake. Thank You.
Here is the Updated patch.

Thanks.
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