The condition "in(select ...)" did not work correctly if the subquery could not…

The condition "in(select ...)" did not work correctly if the subquery could not be converted to a "distinct" query, as in: "select * from dual where x in (select x from dual group by x order by max(x))".

h2/src/docsrc/html/changelog.html

@@ -22,6 +22,7 @@ Change Log
 </li><li>The condition "in(select ...)" did not work correctly if the subquery
     could not be converted to a "distinct" query, as in:
     "select * from dual where x in (select x from dual group by x order by max(x))".
+    Now the subquery needs to be made distinct manually if this optimization is needed.
 </li><li>In the last release, the error code for "Wrong user name or password" was still
     08004 instead of 28000, which resulted in the wrong error message.
 </li><li>In some cases, creating a new table or altering an existing table threw the exception:

h2/src/main/org/h2/expression/ConditionInSelect.java

@@ -118,7 +118,6 @@ public class ConditionInSelect extends Condition {
 
     public Expression optimize(Session session) {
         left = left.optimize(session);
-        query.setDistinct(true);
         query.setRandomAccessResult(true);
         query.prepare();
         if (query.getColumnCount() != 1) {

h2/src/main/org/h2/result/LocalResult.java

@@ -186,15 +186,24 @@ public class LocalResult implements ResultInterface, ResultTarget {
      * @return true if the row exists
      */
     public boolean containsDistinct(Value[] values) {
-        if (!distinct) {
-            DbException.throwInternalError();
+        if (external != null) {
+            return external.contains(values);
+        }
+        if (distinctRows == null) {
+            distinctRows = ValueHashMap.newInstance();
+            for (Value[] row : rows) {
+                if (row.length > visibleColumnCount) {
+                    Value[] r2 = new Value[visibleColumnCount];
+                    System.arraycopy(row, 0, r2, 0, visibleColumnCount);
+                    row = r2;
+                }
+                ValueArray array = ValueArray.get(row);
+                distinctRows.put(array, row);
+            }
         }
-        if (distinctRows != null) {
         ValueArray array = ValueArray.get(values);
         return distinctRows.get(array) != null;
     }
-        return external.contains(values);
-    }
 
     public void reset() {
         rowId = -1;

h2/src/test/org/h2/test/test-1.3.txt

 --- special grammar and test cases ---------------------------------------------------------------------------------------------
+select * from dual where x in (select x from dual group by x order by max(x));
+> X
+> -
+> 1
+> rows (ordered): 1
+
 create table test(d decimal(1, 2));
 > exception
 
@@ -1028,8 +1034,8 @@ insert into t2 select x from system_range(1, 1000);
 
 explain select count(*) from t1 where t1.id in ( select t2.id from t2 );
 > PLAN
-> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
-> SELECT COUNT(*) FROM PUBLIC.T1 /* PUBLIC.PRIMARY_KEY_A: ID IN(SELECT DISTINCT T2.ID FROM PUBLIC.T2 /++ PUBLIC.T2.tableScan ++/) */ WHERE T1.ID IN( SELECT DISTINCT T2.ID FROM PUBLIC.T2 /* PUBLIC.T2.tableScan */)
+> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+> SELECT COUNT(*) FROM PUBLIC.T1 /* PUBLIC.PRIMARY_KEY_A: ID IN(SELECT T2.ID FROM PUBLIC.T2 /++ PUBLIC.T2.tableScan ++/) */ WHERE T1.ID IN( SELECT T2.ID FROM PUBLIC.T2 /* PUBLIC.T2.tableScan */)
 > rows: 1
 
 select count(*) from t1 where t1.id in ( select t2.id from t2 );
@@ -3155,8 +3161,8 @@ where exists (select 1 from test t4 where t2.id=t4.id);
 
 explain select * from test t1 where id in(select id from test t2 where t1.id=t2.id);
 > PLAN
-> -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
-> SELECT T1.ID, T1.NAME FROM PUBLIC.TEST T1 /* PUBLIC.TEST.tableScan */ WHERE ID IN( SELECT DISTINCT ID FROM PUBLIC.TEST T2 /* PUBLIC.PRIMARY_KEY_2: ID = T1.ID */ WHERE T1.ID = T2.ID)
+> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+> SELECT T1.ID, T1.NAME FROM PUBLIC.TEST T1 /* PUBLIC.TEST.tableScan */ WHERE ID IN( SELECT ID FROM PUBLIC.TEST T2 /* PUBLIC.PRIMARY_KEY_2: ID = T1.ID */ WHERE T1.ID = T2.ID)
 > rows: 1
 
 select * from test t1 where id in(select id from test t2 where t1.id=t2.id);
@@ -3194,8 +3200,8 @@ select * from test t1 where id in(id);
 
 explain select * from test t1 where id in(select id from test);
 > PLAN
-> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
-> SELECT T1.ID, T1.NAME FROM PUBLIC.TEST T1 /* PUBLIC.PRIMARY_KEY_2: ID IN(SELECT DISTINCT ID FROM PUBLIC.TEST /++ PUBLIC.TEST.tableScan ++/) */ WHERE ID IN( SELECT DISTINCT ID FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan */)
+> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+> SELECT T1.ID, T1.NAME FROM PUBLIC.TEST T1 /* PUBLIC.PRIMARY_KEY_2: ID IN(SELECT ID FROM PUBLIC.TEST /++ PUBLIC.TEST.tableScan ++/) */ WHERE ID IN( SELECT ID FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan */)
 > rows: 1
 
 select * from test t1 where id in(select id from test);
@@ -6116,14 +6122,14 @@ EXPLAIN PLAN FOR SELECT * FROM TEST T1 WHERE ID IN(1, 2);
 
 EXPLAIN PLAN FOR SELECT * FROM TEST T1 WHERE ID IN(SELECT ID FROM TEST);
 > PLAN
-> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
-> SELECT T1.ID, T1.NAME FROM PUBLIC.TEST T1 /* PUBLIC.PRIMARY_KEY_2: ID IN(SELECT DISTINCT ID FROM PUBLIC.TEST /++ PUBLIC.TEST.tableScan ++/) */ WHERE ID IN( SELECT DISTINCT ID FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan */)
+> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+> SELECT T1.ID, T1.NAME FROM PUBLIC.TEST T1 /* PUBLIC.PRIMARY_KEY_2: ID IN(SELECT ID FROM PUBLIC.TEST /++ PUBLIC.TEST.tableScan ++/) */ WHERE ID IN( SELECT ID FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan */)
 > rows: 1
 
 EXPLAIN PLAN FOR SELECT * FROM TEST T1 WHERE ID NOT IN(SELECT ID FROM TEST);
 > PLAN
-> ---------------------------------------------------------------------------------------------------------------------------------------------------------
-> SELECT T1.ID, T1.NAME FROM PUBLIC.TEST T1 /* PUBLIC.TEST.tableScan */ WHERE NOT (ID IN( SELECT DISTINCT ID FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan */))
+> ------------------------------------------------------------------------------------------------------------------------------------------------
+> SELECT T1.ID, T1.NAME FROM PUBLIC.TEST T1 /* PUBLIC.TEST.tableScan */ WHERE NOT (ID IN( SELECT ID FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan */))
 > rows: 1
 
 EXPLAIN PLAN FOR SELECT CAST(ID AS VARCHAR(255)) FROM TEST;