diff --git a/app/controllers/blazer/base_controller.rb b/app/controllers/blazer/base_controller.rb
index 49faa6117..4a6206926 100644
--- a/app/controllers/blazer/base_controller.rb
+++ b/app/controllers/blazer/base_controller.rb
@@ -47,6 +47,10 @@ def process_vars(statement, data_source)
                 value = value.to_s.gsub(" ", "+") # fix for Quip bug
               end
 
+              if value.is_a?(Array) &&  Blazer.data_sources[data_source].supports_array?
+                value = Blazer.data_sources[data_source].array(value)
+              end
+
               if var.end_with?("_at")
                 begin
                   value = Blazer.time_zone.parse(value)
diff --git a/app/controllers/blazer/queries_controller.rb b/app/controllers/blazer/queries_controller.rb
index d71b33a95..de1fe4267 100644
--- a/app/controllers/blazer/queries_controller.rb
+++ b/app/controllers/blazer/queries_controller.rb
@@ -63,11 +63,14 @@ def show
       process_vars(@statement, @query.data_source)
 
       @smart_vars = {}
+      @plural_vars = {}
       @sql_errors = []
       data_source = Blazer.data_sources[@query.data_source]
       @bind_vars.each do |var|
         smart_var, error = parse_smart_variables(var, data_source)
-        @smart_vars[var] = smart_var if smart_var
+        plural_var, error = parse_smart_variables(var.singularize, data_source) if smart_var.nil? && error.nil?
+        @smart_vars[var] = smart_var || plural_var
+        @plural_vars[var] = true if smart_var.nil? && plural_var.present?
         @sql_errors << error if error
       end
 
diff --git a/app/views/blazer/_variables.html.erb b/app/views/blazer/_variables.html.erb
index d594bcc6e..e01cfb3d0 100644
--- a/app/views/blazer/_variables.html.erb
+++ b/app/views/blazer/_variables.html.erb
@@ -19,7 +19,7 @@
     <% @bind_vars.each_with_index do |var, i| %>
       <%= label_tag var, var %>
       <% if (data = @smart_vars[var]) %>
-        <%= select_tag var, options_for_select([[nil, nil]] + data, selected: params[var]), style: "margin-right: 20px; width: 200px; display: none;" %>
+        <%= select_tag var, options_for_select([[nil, nil]] + data, selected: params[var]), multiple: @plural_vars[var].present?,  style: "margin-right: 20px; width: 200px; display: none;" %>
         <script>
           $("#<%= var %>").selectize({
             create: true
diff --git a/lib/blazer/adapters/base_adapter.rb b/lib/blazer/adapters/base_adapter.rb
index 631c943ef..7dd9834af 100644
--- a/lib/blazer/adapters/base_adapter.rb
+++ b/lib/blazer/adapters/base_adapter.rb
@@ -47,6 +47,14 @@ def supports_cohort_analysis?
         false # optional
       end
 
+      def supports_array?
+        false # optional
+      end
+
+      def array(value)
+        # optional
+      end
+
       def cohort_analysis_statement(statement, period:, days:)
         # optional
       end
diff --git a/lib/blazer/adapters/sql_adapter.rb b/lib/blazer/adapters/sql_adapter.rb
index f2d90a9eb..12467f1ac 100644
--- a/lib/blazer/adapters/sql_adapter.rb
+++ b/lib/blazer/adapters/sql_adapter.rb
@@ -126,6 +126,16 @@ def supports_cohort_analysis?
         postgresql? || mysql?
       end
 
+      def array(value)
+        if postgresql?
+          "{#{value.join(",")}}"
+        end
+      end
+
+      def supports_array?
+        postgresql?
+      end
+
       # TODO treat date columns as already in time zone
       def cohort_analysis_statement(statement, period:, days:)
         raise "Cohort analysis not supported" unless supports_cohort_analysis?
diff --git a/lib/blazer/data_source.rb b/lib/blazer/data_source.rb
index b9de0b084..a34b37980 100644
--- a/lib/blazer/data_source.rb
+++ b/lib/blazer/data_source.rb
@@ -6,7 +6,7 @@ class DataSource
 
     attr_reader :id, :settings
 
-    def_delegators :adapter_instance, :schema, :tables, :preview_statement, :reconnect, :cost, :explain, :cancel, :supports_cohort_analysis?, :cohort_analysis_statement
+    def_delegators :adapter_instance, :schema, :tables, :preview_statement, :reconnect, :cost, :explain, :cancel, :supports_cohort_analysis?, :cohort_analysis_statement, :supports_array?, :array
 
     def initialize(id, settings)
       @id = id