Nested UNION/INTERSECT queries with brackets could produce the wrong result if…

Nested UNION/INTERSECT queries with brackets could produce the wrong result if used within a subquery.

h2/src/docsrc/html/changelog.html

@@ -18,7 +18,9 @@ Change Log
 <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
-<ul><li>Comparing an column against a constant expression with a higher precision or length 
+<ul><li>Nested UNION/INTERSECT queries with brackets could produce the wrong result if used within a subquery. Example:
+    select count(*) from (select 1 union (select 2 intersect select 2)) x; 
+</li><li>Comparing an column against a constant expression with a higher precision or length
     than the column could give wrong results (the expression was truncated before comparing).
 </li><li>Improved PostgreSQL compatibility (support SHOW DEFAULT_TRANSACTION_ISOLATION).
 </li><li>Documentation: the javadocs for Csv.write and read used the wrong default charset.

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

@@ -297,24 +297,24 @@ public class SelectUnion extends Query {
 
     public String getPlanSQL() {
         StringBuilder buff = new StringBuilder();
-        buff.append('(').append(StringUtils.unEnclose(left.getPlanSQL())).append(')');
+        buff.append('(').append(left.getPlanSQL()).append(')');
         switch (unionType) {
         case UNION_ALL:
-            buff.append("UNION ALL ");
+            buff.append(" UNION ALL ");
             break;
         case UNION:
-            buff.append("UNION ");
+            buff.append(" UNION ");
             break;
         case INTERSECT:
-            buff.append("INTERSECT ");
+            buff.append(" INTERSECT ");
             break;
         case EXCEPT:
-            buff.append("EXCEPT ");
+            buff.append(" EXCEPT ");
             break;
         default:
             Message.throwInternalError("type=" + unionType);
         }
-        buff.append('(').append(StringUtils.unEnclose(right.getPlanSQL())).append(')');
+        buff.append('(').append(right.getPlanSQL()).append(')');
         Expression[] exprList = expressions.toArray(new Expression[expressions.size()]);
         if (sort != null) {
             buff.append(" ORDER BY ").append(sort.getSQL(exprList, exprList.length));