[#1524] Simulate ROW_NUMBER() OVER() in HSQLDB using ROWNUM()

jOOQ-test/src/org/jooq/test/_/testcases/AggregateWindowFunctionTests.java

@@ -256,7 +256,6 @@ extends BaseTest<A, AP, B, S, B2S, BS, L, X, DATE, BOOL, D, T, U, I, IPK, T658,
         switch (getDialect()) {
             case ASE:
             case CUBRID:
-            case HSQLDB:
             case INGRES:
             case MYSQL:
             case SQLITE:
@@ -264,8 +263,8 @@ extends BaseTest<A, AP, B, S, B2S, BS, L, X, DATE, BOOL, D, T, U, I, IPK, T658,
                 return;
         }
 
-        // [#1523] Derby now supports the ROW_NUMBER() OVER() window function
-        // without any window clause, though
+        // [#1523] Derby, H2 now support the ROW_NUMBER() OVER() window function
+        // without any window clause, though. HSQLDB can simulate it using ROWNUM()
         List<Integer> rows =
         create().select(rowNumber().over()).from(TBook()).fetch(0, Integer.class);
         assertEquals(asList(1, 2, 3, 4), rows);
@@ -273,6 +272,7 @@ extends BaseTest<A, AP, B, S, B2S, BS, L, X, DATE, BOOL, D, T, U, I, IPK, T658,
         switch (getDialect()) {
             case DERBY:
             case H2:
+            case HSQLDB:
                 log.info("SKIPPING", "Advanced window function tests");
                 return;
         }

jOOQ/src/main/java/org/jooq/WindowOverStep.java

@@ -38,6 +38,7 @@ package org.jooq;
 import static org.jooq.SQLDialect.DB2;
 import static org.jooq.SQLDialect.DERBY;
 import static org.jooq.SQLDialect.H2;
+import static org.jooq.SQLDialect.HSQLDB;
 import static org.jooq.SQLDialect.ORACLE;
 import static org.jooq.SQLDialect.POSTGRES;
 import static org.jooq.SQLDialect.SQLSERVER;
@@ -67,7 +68,7 @@ public interface WindowOverStep<T> {
     /**
      * Add an <code>OVER</code> clause
      */
-    @Support({ DB2, DERBY, H2, POSTGRES, ORACLE, SQLSERVER, SYBASE })
+    @Support({ DB2, DERBY, H2, HSQLDB, POSTGRES, ORACLE, SQLSERVER, SYBASE })
     WindowPartitionByStep<T> over();
 
 }

jOOQ/src/main/java/org/jooq/impl/Factory.java

@@ -50,6 +50,7 @@ import static org.jooq.SQLDialect.SQLITE;
 import static org.jooq.SQLDialect.SQLSERVER;
 import static org.jooq.SQLDialect.SYBASE;
 import static org.jooq.conf.SettingsTools.getRenderMapping;
+import static org.jooq.impl.Term.ROW_NUMBER;
 import static org.jooq.impl.Util.combine;
 
 import java.io.IOException;
@@ -5101,11 +5102,13 @@ public class Factory implements FactoryOperations {
      * <p>
      * Newer versions of {@link SQLDialect#DERBY} and {@link SQLDialect#H2} also
      * support the <code>ROW_NUMBER() OVER()</code> window function without any
-     * window clause. See the respective docs for details
+     * window clause. See the respective docs for details.
+     * {@link SQLDialect#HSQLDB} can simulate this function using
+     * <code>ROWNUM()</code>
      */
-    @Support({ DB2, DERBY, H2, POSTGRES, ORACLE, SQLSERVER, SYBASE })
+    @Support({ DB2, DERBY, H2, HSQLDB, POSTGRES, ORACLE, SQLSERVER, SYBASE })
     public static WindowOverStep<Integer> rowNumber() {
-        return new Function<Integer>("row_number", SQLDataType.INTEGER);
+        return new Function<Integer>(ROW_NUMBER, SQLDataType.INTEGER);
     }
 
     /**

jOOQ/src/main/java/org/jooq/impl/Function.java

@@ -46,6 +46,7 @@ import static org.jooq.SQLDialect.POSTGRES;
 import static org.jooq.SQLDialect.SYBASE;
 import static org.jooq.impl.Factory.one;
 import static org.jooq.impl.Term.LIST_AGG;
+import static org.jooq.impl.Term.ROW_NUMBER;
 
 import java.util.Arrays;
 import java.util.Collection;
@@ -299,7 +300,16 @@ class Function<T> extends AbstractField<T> implements
     }
 
     private final void toSQLOverClause(RenderContext context) {
-        if (!over) return;
+
+        // Render this clause only if needed
+        if (!over) {
+            return;
+        }
+
+        // [#1524] Don't render this clause where it is not supported
+        if (over && term == ROW_NUMBER && context.getDialect() == HSQLDB) {
+            return;
+        }
 
         String glue = "";
         context.keyword(" over (");

jOOQ/src/main/java/org/jooq/impl/Term.java

@@ -149,6 +149,17 @@ enum Term {
             return "octet_length";
         }
     },
+    ROW_NUMBER {
+        @Override
+        public String translate(SQLDialect dialect) {
+            switch (dialect) {
+                case HSQLDB:
+                    return "rownum";
+            }
+
+            return "row_number";
+        }
+    },
     STDDEV_POP {
         @Override
         public String translate(SQLDialect dialect) {