20th May 2021:
PostgreSQL 14 Beta 1 Released!

This documentation is for an unsupported version of PostgreSQL.

You may want to view the same page for the current version, or one of the other supported versions listed above instead.

You may want to view the same page for the current version, or one of the other supported versions listed above instead.

PostgreSQL 9.2.24 Documentation | ||||
---|---|---|---|---|

Prev | Up | Chapter 9. Functions and Operators | Next |

Mathematical operators are provided for many PostgreSQL types. For types without standard mathematical conventions (e.g., date/time types) we describe the actual behavior in subsequent sections.

Table 9-2 shows the available mathematical operators.

Table 9-2. Mathematical Operators

Operator | Description | Example | Result |
---|---|---|---|

+ |
addition | 2 + 3 |
5 |

- |
subtraction | 2 - 3 |
-1 |

* |
multiplication | 2 * 3 |
6 |

/ |
division (integer division truncates the result) | 4 / 2 |
2 |

% |
modulo (remainder) | 5 % 4 |
1 |

^ |
exponentiation (associates left to right) | 2.0 ^ 3.0 |
8 |

|/ |
square root | |/ 25.0 |
5 |

||/ |
cube root | ||/ 27.0 |
3 |

! |
factorial | 5 ! |
120 |

!! |
factorial (prefix operator) | !! 5 |
120 |

@ |
absolute value | @ -5.0 |
5 |

& |
bitwise AND | 91 & 15 |
11 |

| |
bitwise OR | 32 | 3 |
35 |

# |
bitwise XOR | 17 # 5 |
20 |

~ |
bitwise NOT | ~1 |
-2 |

<< |
bitwise shift left | 1 << 4 |
16 |

>> |
bitwise shift right | 8 >> 2 |
2 |

The bitwise operators work only on integral data types,
whereas the others are available for all numeric data types. The
bitwise operators are also available for the bit string types
`bit` and `bit varying`,
as shown in Table
9-11.

Table
9-3 shows the available mathematical functions. In the table,
`dp` indicates `double
precision`. Many of these functions are provided in multiple
forms with different argument types. Except where noted, any
given form of a function returns the same data type as its
argument. The functions working with `double
precision` data are mostly implemented on top of the host
system's C library; accuracy and behavior in boundary cases can
therefore vary depending on the host system.

Table 9-3. Mathematical Functions

Function | Return Type | Description | Example | Result |
---|---|---|---|---|

`abs(` |
(same as input) | absolute value | abs(-17.4) |
17.4 |

`cbrt(` |
dp |
cube root | cbrt(27.0) |
3 |

`ceil(` |
(same as input) | nearest integer greater than or equal to argument | ceil(-42.8) |
-42 |

`ceiling(` |
(same as input) | nearest integer greater than or equal to argument
(same as `ceil` ) |
ceiling(-95.3) |
-95 |

`degrees(` |
dp |
radians to degrees | degrees(0.5) |
28.6478897565412 |

`div(` |
numeric |
integer quotient of y/x |
div(9,4) |
2 |

`exp(` |
(same as input) | exponential | exp(1.0) |
2.71828182845905 |

`floor(` |
(same as input) | nearest integer less than or equal to argument | floor(-42.8) |
-43 |

`ln(` |
(same as input) | natural logarithm | ln(2.0) |
0.693147180559945 |

`log(` |
(same as input) | base 10 logarithm | log(100.0) |
2 |

`log(` |
numeric |
logarithm to base b |
log(2.0, 64.0) |
6.0000000000 |

`mod(` |
(same as argument types) | remainder of y/x |
mod(9,4) |
1 |

`pi()` |
dp |
"π" constant | pi() |
3.14159265358979 |

`power(` |
dp |
a raised to the power of
b |
power(9.0, 3.0) |
729 |

`power(` |
numeric |
a raised to the power of
b |
power(9.0, 3.0) |
729 |

`radians(` |
dp |
degrees to radians | radians(45.0) |
0.785398163397448 |

`round(` |
(same as input) | round to nearest integer | round(42.4) |
42 |

`round(` |
numeric |
round to s decimal
places |
round(42.4382, 2) |
42.44 |

`sign(` |
(same as input) | sign of the argument (-1, 0, +1) | sign(-8.4) |
-1 |

`sqrt(` |
(same as input) | square root | sqrt(2.0) |
1.4142135623731 |

`trunc(` |
(same as input) | truncate toward zero | trunc(42.8) |
42 |

`trunc(` |
numeric |
truncate to s decimal
places |
trunc(42.4382, 2) |
42.43 |

`width_bucket(` |
int |
return the bucket to which operand would be assigned in an
equidepth histogram with count
buckets, in the range b1 to
b2 |
width_bucket(5.35, 0.024, 10.06,
5) |
3 |

`width_bucket(` |
int |
return the bucket to which operand would be assigned in an
equidepth histogram with count
buckets, in the range b1 to
b2 |
width_bucket(5.35, 0.024, 10.06,
5) |
3 |

Table 9-4 shows functions for generating random numbers.

Table 9-4. Random Functions

Function | Return Type | Description |
---|---|---|

`random()` |
dp |
random value in the range 0.0 <= x < 1.0 |

`setseed(` |
void |
set seed for subsequent random() calls (value between -1.0 and
1.0, inclusive) |

The characteristics of the values returned by ` random()` depend on
the system implementation. It is not suitable for cryptographic
applications; see pgcrypto module for
an alternative.

Finally, Table 9-5
shows the available trigonometric functions. All trigonometric
functions take arguments and return values of type `double precision`. Trigonometric functions arguments
are expressed in radians. Inverse functions return values are
expressed in radians. See unit transformation functions
` radians()`
and

`degrees()`