Enable multiple default columns

lib/text_to_sql_query.rb

@@ -1,10 +1,17 @@
 require_relative 'parser'
 
 class TextToSqlQuery
-  def initialize(text, fields, default_field, fields_mappings = {})
+  def initialize(text, fields, default_fields, fields_mappings = {})
     @text = text.to_s.strip
     @fields = fields.map(&:to_sym)
-    @default_field = default_field.to_sym
+
+    # Keep compatibility with previous version where default_field(s) was string/symbol
+    @default_fields = if default_fields.is_a? Array
+                        default_fields.map(&:to_sym)
+                      else
+                        [default_fields.to_sym]
+                      end
+
     @fields_mappings = fields_mappings.merge(@fields.reduce({}) do |mappings, field|
       _table_name, field_name = field.to_s.split('.')
       mappings[field_name.to_sym] = field
@@ -29,7 +36,14 @@ class TextToSqlQuery
     case first_key
     when :DEFAULT_COLUMN
       escaped_node_value = handle_special_chars node_value
-      ["CAST(#{@default_field.to_s} AS TEXT) ILIKE ?", "%#{escaped_node_value}%"]
+      query_part = '('
+      params_part = []
+      @default_fields.each do |default_field|
+        query_part += "CAST(#{default_field.to_s} AS TEXT) ILIKE ? OR "
+        params_part << "%#{escaped_node_value}%"
+      end
+      query_part = query_part[0...-4] + ')'
+      [query_part, *params_part]
     when :OPERATOR_OR
       generate_expression_for_logical_operator(:OR, node_value)
     when :OPERATOR_AND