anchor.diff:  <<<
   [[select_examples]]
   === Examples of SELECT
  +
  +* The following example defines two CTEs, w1 and w2. w2 references w1 which is defined before w2.
  +```
  +>>select * from t1
  +
  + C1 C2
  + ----------
  +
  +  1 1
  +  2 2
  +  3 3
  +  4 4
  +  5 5
  +
  + --- SQL operation complete.
  +
  +>>with w1 as (select * from t1),
  +>>w2 as (select * from w1)
  +>>select * from w2;
  +
  + C1 C2
  + ----------
  +
  +  1 1
  +  2 2
  +  3 3
  +  4 4
  +  5 5
  +
  + --- SQL operation complete.
  +```
  +
  +* The following example defines two CTEs, w1 and w2, and then perform a JOIN between them.
  +```
  +>>select * from t1
  +
  + C1 C2
  + ----------
  +
  +  1 1
  +  2 2
  +  3 3
  +  4 4
  +  5 5
  +
  + --- SQL operation complete.
  +
  +>>select * from t2
  +
  + C1 C2
  + ----------
  +
  +  3 3
  +  4 4
  +  5 5
  +  6 6
  +  7 7
  +
  + --- SQL operation complete.
  +
  +>>with w1 as (select c1, c2 from t1),
  +>>w2 as (select c1, c2 from t2)
  +>>select * from w1, w2 where w1.c1 = w2.c1;
  +
  + C1 C2 C1 C2
  + ----------
  +
  +  3 3 3 3
  +  4 4 4 4
  +  5 5 5 5
  +
  + --- SQL operation complete.
  +```
   
   * Retrieve information from the EMPLOYEE table for employees with a job code greater than 500 and who are in departments
   with numbers less than or equal to 3000, displaying the results in ascending order by job code:
  
positive.code:    [access-clause ]
     [mode-clause]
  
  query-expr-and-order is:
      query-expr [order-by-clause] [access-clause] [mode-clause]
  
  
negative.code: SELECT a+1 FROM t GROUP BY 1+a;
  ```
  
  <<<
  [[set_schema_statement]]
  == SET SCHEMA Statement
  