Allow unrestricted ORDER BY with DISTINCT only in MySQL mode

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

@@ -12,6 +12,7 @@ import org.h2.api.ErrorCode;
 import org.h2.command.Prepared;
 import org.h2.engine.Database;
 import org.h2.engine.Session;
+import org.h2.engine.Mode.ModeEnum;
 import org.h2.expression.Alias;
 import org.h2.expression.Expression;
 import org.h2.expression.ExpressionColumn;
@@ -478,8 +479,9 @@ public abstract class Query extends Prepared {
             }
             if (!isAlias) {
                 if (mustBeInResult) {
-                    throw DbException.get(ErrorCode.ORDER_BY_NOT_IN_RESULT,
-                            e.getSQL());
+                    if (session.getDatabase().getMode().getEnum() != ModeEnum.MySQL) {
+                        throw DbException.get(ErrorCode.ORDER_BY_NOT_IN_RESULT, e.getSQL());
+                    }
                 }
                 expressions.add(e);
                 String sql = e.getSQL();

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

@@ -835,7 +835,7 @@ public class Select extends Query {
         }
         if (orderList != null) {
             initOrder(session, expressions, expressionSQL, orderList,
-                    visibleColumnCount, false, filters);
+                    visibleColumnCount, distinct, filters);
         }
         distinctColumnCount = expressions.size();
         if (having != null) {

h2/src/test/org/h2/test/scripts/distinct.sql

@@ -15,6 +15,9 @@ CREATE TABLE TEST2(ID2 BIGINT);
 INSERT INTO TEST2 VALUES (1), (2);
 > update count: 2
 
+SET MODE MySQL;
+> ok
+
 SELECT DISTINCT ID FROM TEST ORDER BY NAME;
 > ID
 > --
@@ -38,6 +41,9 @@ SELECT DISTINCT ID FROM TEST JOIN TEST2 ON ID = ID2 ORDER BY LOWER(NAME);
 > 2
 > rows (ordered): 2
 
+SET MODE Regular;
+> ok
+
 DROP TABLE TEST;
 > ok