no message

function_convert_weight.sql

@@ -0,0 +1,33 @@
+CREATE OR REPLACE FUNCTION convert_weight(
+    p_value numeric,
+    p_from_unit text,
+    p_to_unit text
+)
+RETURNS numeric
+LANGUAGE plpgsql
+AS $$
+DECLARE
+    v_from_factor numeric;
+    v_to_factor   numeric;
+BEGIN
+    SELECT factor INTO v_from_factor
+    FROM product_uom
+    WHERE lower(name) = lower(p_from_unit);
+
+    IF v_from_factor IS NULL THEN
+        RAISE EXCEPTION 'Unknown source unit: %', p_from_unit;
+    END IF;
+
+    SELECT factor INTO v_to_factor
+    FROM product_uom
+    WHERE lower(name) = lower(p_to_unit);
+
+    IF v_to_factor IS NULL THEN
+        RAISE EXCEPTION 'Unknown target unit: %', p_to_unit;
+    END IF;
+
+    RETURN p_value * v_from_factor / v_to_factor;
+END;
+$$;
+
+