Arithmetic Functions and Operators

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

  1. The DIV, MOD, XOR, and ^ operators are added.
  2. The truncate, rand, crc32, conv, float8_bool, oct, and float4_bool functions are added.
  3. Implement the atan function to support the usage of atan(y, x).
  • DIV

    Description: Division (rounded)

    Example:

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

    Description: Model (to obtain the remainder)

    Example:

    openGauss=# SELECT 4 MOD 3 AS RESULT;
     result 
    --------
          1
    (1 row)
    
  • XOR

    Description: Binary XOR

    Example:

    openGauss=# 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:

    openGauss=# 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:

    openGauss=# SELECT rand();
           rand
    -------------------
     0.254671605769545
    (1 row)
    
  • crc32(string)

    Description: Calculates the crc32 value of string.

    Return type: int

    Example:

    openGauss=# 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:

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

    Description: Implements bitwise XOR between two integers.

    Return type: INT

    Example:

    openGauss=# SELECT 1^1;
    ?column?
    ----------
           0
    (1 row)
    

    Description: After set b_compatibility_mode is set to 1, the float data can be bitwise XOR or XOR after rounded off.

    Return type: DOUBLE

    Example:

    openGauss=# select 0.5678::float^1.1234::float;
     ?column? 
    ----------
            0
    (1 row)
    
  • float8_bool(float)

    Description: Returns a Boolean value based on the value of a floating point number. If the value is 0, false is returned. Otherwise, true is returned.

    Return type: Boolean

    Example:

    openGauss=# select float8_bool(0.1);
     float8_bool 
    -------------
     t
    (1 row)
    
    openGauss=# select float8_bool(0.0);
     float8_bool 
    -------------
     f
    (1 row)
    
  • oct(input N)

    Description: Converts a number or string from a decimal number to an octal number.

    Return type: text

    Example:

    openGauss=# SELECT OCT(10);
     oct 
    -----
    12
    (1 row)
    
    openGauss=# SELECT OCT('10');
     oct 
    -----
    12
    (1 row)
    
  • float4_bool(float)

    Description: Returns a Boolean value based on the value of a floating point number. If the value is 0, false is returned. Otherwise, true is returned.

    Return type: Boolean

    Example:

    openGauss=# select float4_bool(0.1);
     float4_bool 
    -------------
     t
    (1 row)
    
    openGauss=# select float4_bool(0.0);
     float4_bool 
    -------------
     f
    (1 row)
    
  • atan(y, x)

    Description: Arc tangent of y/x.

    Return type: double precision

    Example:

    openGauss=# SELECT atan(2, 1);
          atan
    ------------------
     1.10714871779409
    (1 row)
    
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    openGauss 2024-11-09 00:55:16
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