Handle sparse results

c-historico/handler.cr

@@ -97,14 +97,17 @@ class Handler
         x = Array(Int32).new
         y = Array(Int32).new
         results = query(sql)
-        if results.nil?  # No results, all 0s
+        if results.nil? # No results, all 0s
           x = (1922..2015).to_a
-          y = x.map {|_| 0}
-        else  # We got results
-          displayed = true
+          y = x.map { |_| 0 }
+        else # We got results
+          values = Hash(Int32, Int32).new(default_value: 0)
           results.map { |r|
-            x << r[0].as_i
-            y << r[1].as_i
+            values[r[0].as_i] = r[1].as_i
+          }
+          (1922..2015).map { |year|
+            x << year
+            y << values[year]  # Defaults to 0, so we have the whole set
           }
         end
         plot(x, y, title: nombre.titleize, style: :lines, linewidth: 3)