Arithmetic Functions and Operators

Compared with the original MogDB, Dolphin modifies the time/date function as follows:

1. The DIV, MOD, and XOR operators are added.
2. The truncate, rand, crc32, conv functions are added.

• DIV

  Description: Division (rounded)

  Example:

  MogDB=# SELECT 8 DIV 3 AS RESULT;
   result 
  --------
        2
  (1 row)

• MOD

  Description: Model (to obtain the remainder)

  Example:

  MogDB=# SELECT 4 MOD 3 AS RESULT;
   result 
  --------
        1
  (1 row)

• XOR

  Description: Binary XOR

  Example:

  MogDB=# SELECT 4 XOR 3 AS RESULT;
   result 
  --------
        0
  (1 row)

• truncate(v numeric, s int)

  Description: Truncates a number with s digits after the decimal point. It is equivalent to trunc.

  Return type: numeric

  Example:

  MogDB=# SELECT truncate(42.4382, 2);
   truncate
  ----------
      42.43
  (1 row)

• rand()

  Description: Random number between 0.0 and 1.0 It is equivalent to random.

  Return type: double precision

  Example:

  MogDB=# SELECT rand();
         rand
  -------------------
   0.254671605769545
  (1 row)

• crc32(string)

  Description: Calculates the crc32 value of string.

  Return type: int

  Example:

  MogDB=# SELECT crc32('abc');
     crc32
  -----------
   891568578
  (1 row)

• conv(input in, current_base int, new_base int)

  Description: Converts a number or string from one number base system to another. The value of in can be a number or a character string.

  Return type: text

  Example:

  MogDB=# SELECT conv(20, 10, 2);
   conv
  -------
   10100
  (1 row)
      
  MogDB=# SELECT conv('8D', 16, 10);
   conv
  ------
   141
  (1 row)