SELECT  SYS.database_name,
 sys.standard.sqlcode  SQL_CODE,
 sys.standard.sqlerrm  SQL_ERRM 
FROM DUAL;

SELECT sys.standard.sqlerrm(-level) sql_errm
FROM DUAL CONNECT BY level <= 20;

--> First 20 Error Messges

--Reference Temperature conversion (F to C and C to F)

SELECT  q_t.i_deg  f_deg,  ((q_t.i_deg-32)/9)*5 c_deg,
        q_t.i_deg  c_deg,  ((q_t.i_deg*9)/5)+32 f_deg
FROM (SELECT &i_deg  i_deg  FROM DUAL) q_t;

--The Directory Path (server)

SELECT level, SYS_CONNECT_BY_PATH('/', '..') dir_path 
FROM DUAL CONNECT BY LEVEL < 5;

--The Calendar Summary

SELECT 
  level month_no, 
  NTILE(4) OVER (ORDER BY level) As Quarter, 
  TO_CHAR(ADD_MONTHS(TRUNC(SYSDATE,'year'),level-1),'mm/dd/yyyy') start_date, 
  TO_CHAR(LAST_DAY(ADD_MONTHS(TRUNC(SYSDATE,'year'),level-1)),'mm/dd/yyyy') end_date, 
  LAST_DAY(ADD_MONTHS(TRUNC(SYSDATE,'year'),level-1))- ADD_MONTHS(TRUNC(SYSDATE,'year'),level-1)+1 month_days, 
  SUM(LAST_DAY(ADD_MONTHS(TRUNC(SYSDATE,'year'),level-1)) - ADD_MONTHS(TRUNC(SYSDATE,'year'),level-1)+1)
     OVER (ORDER BY level) ytd_days 
FROM DUAL
 CONNECT BY level <= 12;

--The ASCII Table
SELECT level, chr(level) chr_value FROM DUAL CONNECT BY level <= 256;

--Random Number, dbms_crypto.randombytes

SELECT
 ROUND(10000*DBMS_RANDOM.value) val1,
 ROUND(10000*DBMS_RANDOM.value) val2
 -- , dbms_crypto.randombytes(1) dc_val   -- priv
FROM DUAL;

--SQL Model Clause (Oracle documentation)

SELECT x, s FROM DUAL
MODEL 
  DIMENSION BY (1 AS x) MEASURES (1024 AS s)
  RULES UPDATE ITERATE (5)
   (s[1] = s[1]/2);


SELECT x, s, iterations FROM DUAL
MODEL 
  DIMENSION BY (1 AS x) MEASURES (1024 AS s, 0 AS iterations)
  RULES ITERATE (1000)  UNTIL ABS(PREVIOUS(s[1]) - s[1]) < 1
 (s[1] = s[1]/2, iterations[1] = ITERATION_NUMBER);

--The range of values is as shown below for Julian Date 

SELECT
 TO_CHAR(TO_DATE(1,'J'),'JSP') min_number_str,
 TO_CHAR(TO_DATE(5373484,'J'),'JSP') max_number_str
FROM DUAL;