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:

CREATE TABLE emp2 AS SELECT * FROM employees;

ALTER TABLE emp2 ADD (income AS (salary + (salary*commission_pct)));

CREATE TABLE emp (deptno NUMBER, empname VARCHAR(32), grade NUMBER)   
     PARTITION BY RANGE(deptno) SUBPARTITION BY HASH(empname)
        SUBPARTITIONS 8 STORE IN (ts1, ts3, ts5, ts7)
    (PARTITION p1 VALUES LESS THAN (1000),
     PARTITION p2 VALUES LESS THAN (2000)
        STORE IN (ts2, ts4, ts6, ts8),
     PARTITION p3 VALUES LESS THAN (MAXVALUE)
       (SUBPARTITION p3_s1 TABLESPACE ts4,
        SUBPARTITION p3_s2 TABLESPACE ts5));

CREATE TABLE emp_load
             (first_name CHAR(15),
              last_name CHAR(20),
              resume CHAR(2000),
              picture RAW(2000))
  ORGANIZATION EXTERNAL
  (TYPE ORACLE_LOADER
   DEFAULT DIRECTORY ext_tab_dir
   ACCESS PARAMETERS
     (RECORDS
        VARIABLE 2
        DATA IS BIG ENDIAN
        CHARACTERSET US7ASCII
      FIELDS (first_name VARCHAR(2,12),
              last_name VARCHAR(2,20),
              resume VARCHAR(4,10000),
              picture VARRAW(4,100000)))
    LOCATION ('info.dat'));

CREATE TABLE emp_load
             (first_name CHAR(15),
              last_name CHAR(20),
              resume CHAR(2000),
              picture RAW (2000))
  ORGANIZATION EXTERNAL
  (TYPE ORACLE_LOADER
    DEFAULT DIRECTORY ext_tab_dir
    ACCESS PARAMETERS
      (FIELDS (first_name VARCHARC(5,12),
               last_name VARCHARC(2,20),
               resume VARCHARC(4,10000),
               picture VARRAWC(4,100000)))
  LOCATION ('info.dat'));

CREATE TABLE dept_hash
   PARTITION BY HASH(department_id)
   PARTITIONS 3
   PARALLEL 2
   AS SELECT * FROM departments;

EXPLAIN PLAN FOR SELECT /*+ PQ_DISTRIBUTE(e NONE NONE) ORDERED */ e.last_name,
       d.department_name
  FROM emp_comp e, dept_hash d
 WHERE e.department_id = d.department_id;

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