Support for null-safe equals. This includes the ANSI SQL standard syntax A IS…

Support for null-safe equals. This includes the ANSI SQL standard syntax A IS [NOT] DISTINCT FROM B as well as the shorter A IS [NOT] B.

h2/src/main/org/h2/command/dml/Select.java

@@ -1065,7 +1065,7 @@ public class Select extends Query {
             comp = new Comparison(session, comparisonType, col, param);
         } else {
             // add the parameters, so they can be set later
-            comp = new Comparison(session, Comparison.EQUAL, param, param);
+            comp = new Comparison(session, Comparison.EQUAL_NULL_SAFE, param, param);
         }
         comp = comp.optimize(session);
         boolean addToCondition = true;