Because MySQL can't abide parentheses around its intervals, let's put

them around the entire expression rather than around the operands
(which matches the behavior of the binary operator method).

src/main/java/com/samskivert/depot/impl/BuildVisitor.java

@@ -157,15 +157,15 @@ public abstract class BuildVisitor implements FragmentVisitor<Void>
 
     public Void visit (MultiOperator<?> multiOperator)
     {
+        _builder.append('(');
         SQLExpression<?>[] conditions = multiOperator.getArgs();
         for (int ii = 0; ii < conditions.length; ii++) {
             if (ii > 0) {
                 _builder.append(" ").append(multiOperator.operator()).append(" ");
             }
-            _builder.append("(");
             conditions[ii].accept(this);
-            _builder.append(")");
         }
+        _builder.append(")");
         return null;
     }