FlyingZC opened a new issue, #27129:
URL: https://github.com/apache/shardingsphere/issues/27129

   # Background
   Hi community,
   This issue is for #26878.
   
   ShardingSphere parser engine helps users parse a SQL to get the AST 
(Abstract Syntax Tree) and visit this tree to get SQLStatement (Java Object). 
Currently, we are planning to enhance the support for Oracle SQL parsing in 
ShardingSphere.
   
   More details:
   
https://shardingsphere.apache.org/document/current/en/reference/sharding/parse/
   
   # Task
   This issue is to support more oracle sql parse, as follows:
   ```sql
   CREATE VIEW v AS
     SELECT e.last_name, e.department_id, d.location_id
     FROM employees e, departments d
     WHERE e.department_id = d.department_id;
    
   CREATE TABLE t AS
     SELECT * from employees
     WHERE employee_id < 200;
   ```
   
   ```sql
   CREATE VIEW v_depts OF depts_t WITH OBJECT IDENTIFIER (deptno) AS
     SELECT d.deptno, d.deptname, 
       CAST(MULTISET(SELECT e.ename, e.salary, e.deptname,
           CAST(MULTISET(SELECT p.projname, p.mgr
             FROM projects p
             WHERE p.mgr = e.ename)
           AS nt_project_t)
         FROM emps e
         WHERE e.deptname = d.deptname)
       AS nt_emp_t)
     FROM depts d;
   ```
   
   ```sql
   CREATE VIEW warehouse_view AS
      SELECT VALUE(p) AS warehouse_xml
      FROM xwarehouses p;
   ```
   
   ```sql
   CREATE VIEW time_view AS
   SELECT time_id, TO_NUMBER(TO_CHAR(time_id, 'ddd')) AS day_in_year FROM times;
   ```
   
   ```sql
   CREATE VIEW view_with_unionall AS
   (SELECT c.rowid crid, c.cust_id, 2 umarker
    FROM customers c WHERE c.cust_last_name = 'Smith'
    UNION ALL
    SELECT c.rowid crid, c.cust_id, 3 umarker
    FROM customers c WHERE c.cust_last_name = 'Jones');
   
   CREATE MATERIALIZED VIEW unionall_inside_view_mv
   REFRESH FAST ON DEMAND AS
   SELECT * FROM view_with_unionall;
   ```
   
   # Process
   1. First confirm that this is a correct oracle sql syntax, if not please 
ignore;
   2. Compare SQL definitions in Oficial SQL Doc and ShardingSphere SQL Doc;
   3. If there is any difference in ShardingSphere SQL Doc, please correct them 
by referring to the Official SQL Doc;
   4. Run mvn install the current_file_module;
   5. Check whether there are any exceptions. If indeed, please fix them. 
(Especially xxxVisitor.class);
   6. Add new corresponding SQL case in SQL Cases and expected parsed result in 
Expected Statment XML;
   7. Run SQLParserParameterizedTest to make sure no exceptions.
   
   # Relevant Skills
   1. Master JAVA language
   2. Have a basic understanding of Antlr `g4` file
   3. Be familiar with Oracle SQLs


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