bug fix for #4042

src/main/java/com/alibaba/druid/sql/parser/SQLExprParser.java

@@ -4855,7 +4855,7 @@ public class SQLExprParser extends SQLParser {
         if (lexer.token == Token.ON) {
             lexer.nextToken();
             accept(Token.DELETE);
-            if (lexer.identifierEquals(FnvHash.Constants.CASCADE)) {
+            if (lexer.identifierEquals(FnvHash.Constants.CASCADE) || lexer.token == Token.CASCADE) {
                 lexer.nextToken();
                 fk.setOnDeleteCascade(true);
             } else {

src/test/java/com/alibaba/druid/bvt/sql/postgresql/PostgresqlResourceTest.java

@@ -44,6 +44,10 @@ public class PostgresqlResourceTest extends PGTest {
         exec_test("bvt/parser/postgresql-1.txt");
     }
 
+    public void test_2() throws Exception {
+        exec_test("bvt/parser/postgresql-2.txt");
+    }
+
     public void exec_test(String resource) throws Exception {
         System.out.println(resource);
         InputStream is = null;

src/test/resources/bvt/parser/postgresql-2.txt

@@ -0,0 +1,14 @@
+alter table ACT_RU_INTEGRATION
+    add constraint ACT_FK_INT_EXECUTION
+        foreign key (EXECUTION_ID_)
+            references ACT_RU_EXECUTION (ID_)
+        on delete cascade
+---------------------------
+SELECT e1.last_name
+FROM employees e1
+WHERE f(CURSOR((
+	SELECT e2.hire_date
+	FROM employees e2
+	WHERE e1.employee_id = e2.manager_id
+	)), e1.hire_date) = 1
+ORDER BY last_name;