dialect(oracle): an inner join is written with JOIN ... ON

dialect/db/oracle/src/main/java/org/eclipse/daanse/sql/dialect/db/oracle/OracleDialect.java

@@ -266,10 +266,9 @@ public StringBuilder generateOrderByNulls(CharSequence expr, boolean ascending,
         return generateOrderByNullsAnsi(expr, ascending, collateNullsLast);
     }
 
-    @Override
-    public boolean allowsJoinOn() {
-        return false;
-    }
+    // No allowsJoinOn override: Oracle reads ANSI JOIN ... ON since 9i. The false it returned was an inherited
+    // base-class default rather than a reason of Oracle's, and Oracle alone wrote comma joins with the join
+    // condition in WHERE (database run 19./20.10., the drill-through statements; F-10.6 5a).
 
     @Override
     public boolean allowsRegularExpressionInWhereClause() {

dialect/db/oracle/src/test/java/org/eclipse/daanse/sql/dialect/db/oracle/OracleDialectTest.java

@@ -44,6 +44,12 @@ public void setUp() throws Exception {
         dialect = new OracleDialect(org.eclipse.daanse.sql.dialect.api.DialectInitData.fromConnection(connection));
     }
 
+    /** Oracle reads ANSI joins; comma joins were the inherited default, not an Oracle limit. */
+    @Test
+    void anInnerJoinIsWrittenWithJoinOn() {
+        assertTrue(dialect.allowsJoinOn());
+    }
+
     @Test
     void testAllowsRegularExpressionInWhereClause() {
         assertTrue(dialect.allowsRegularExpressionInWhereClause());