Queries "group by" that contain a subquery with an aggregate function returned…

Queries "group by" that contain a subquery with an aggregate function returned the wrong result in some cases.

h2/src/docsrc/html/changelog.html

@@ -21,6 +21,8 @@ Change Log
 <ul><li>Improved spatial index and data type.
 </li><li>Issue 467: OSGi Class Loader (ability to create reference to class
     in other ClassLoader, for example in another OSGi bundle).
+</li><li>Queries "group by" that contain a subquery with an aggregate function
+    returned the wrong result in some cases.
 </li><li>Fix bug in unique and non-unique hash indexes which manifested as incorrect results
     when the search key was a different cardinal type from the table index key.
     e.g. where the one was INT and the other was LONG

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

@@ -160,7 +160,8 @@ public class Select extends Query {
     private void queryGroupSorted(int columnCount, ResultTarget result) {
         int rowNumber = 0;
         setCurrentRowNumber(0);
-        Value[] previousKeyValues = null;
+        currentGroup = null;
+        Value[] previousKeyValues = null;    
         while (topTableFilter.next()) {
             setCurrentRowNumber(rowNumber + 1);
             if (condition == null || Boolean.TRUE.equals(condition.getBooleanValue(session))) {
@@ -312,6 +313,7 @@ public class Select extends Query {
         ValueHashMap<HashMap<Expression, Object>> groups = ValueHashMap.newInstance();
         int rowNumber = 0;
         setCurrentRowNumber(0);
+        currentGroup = null;
         ValueArray defaultGroup = ValueArray.get(new Value[0]);
         while (topTableFilter.next()) {
             setCurrentRowNumber(rowNumber + 1);
@@ -604,8 +606,6 @@ public class Select extends Query {
                 throw DbException.getUnsupportedException("FOR UPDATE && AGGREGATE");
             } else if (topTableFilter.getJoin() != null) {
                 throw DbException.getUnsupportedException("FOR UPDATE && JOIN");
-            } else if (topTableFilter.getJoin() != null) {
-                throw DbException.getUnsupportedException("FOR UPDATE && JOIN");
             }
         }
         topTableFilter.lock(session, exclusive, exclusive);

h2/src/test/org/h2/test/db/TestOptimizations.java

@@ -40,6 +40,7 @@ public class TestOptimizations extends TestBase {
     @Override
     public void test() throws Exception {
         deleteDb("optimizations");
+        testGroupSubquery();
         testAnalyzeLob();
         testLike();
         testExistsSubquery();
@@ -73,6 +74,28 @@ public class TestOptimizations extends TestBase {
         testConvertOrToIn();
         deleteDb("optimizations");
     }
+    
+    private void testGroupSubquery() throws Exception {
+        Connection conn = getConnection("optimizations");
+        Statement stat = conn.createStatement();
+        stat.execute("create table t1(id int)");
+        stat.execute("create table t2(id int)");
+        stat.execute("insert into t1 values(2), (2), (3)");
+        stat.execute("insert into t2 values(2), (3)");
+        stat.execute("create index t1id_index on t1(id)");
+        ResultSet rs;
+        rs = stat.executeQuery("select id, (select count(*) from t2 " + 
+                "where t2.id = t1.id) cc from t1 group by id order by id");
+        rs.next();
+        assertEquals(2, rs.getInt(1));
+        assertEquals(1, rs.getInt(2));
+        rs.next();
+        assertEquals(3, rs.getInt(1));
+        assertEquals(1, rs.getInt(2));
+        rs.next();
+        stat.execute("drop table t1, t2");
+        conn.close();
+    }
 
     private void testAnalyzeLob() throws Exception {
         Connection conn = getConnection("optimizations");