Mathematical operators are provided for many PostgreSQL types. For types without common mathematical conventions for all possible permutations (e.g., date/time types) we describe the actual behavior in subsequent sections.
Table 9.2, “Mathematical Operators” 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 results) | 4 / 2 |
2 |
% |
modulo (remainder) | 5 % 4 |
1 |
^ |
exponentiation | 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 9.10, “Bit String Operators”.
Table 9.3, “Mathematical Functions” 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 may therefore vary depending on the host system.
Table 9.3. Mathematical Functions
Function | Return Type | Description | Example | Result |
---|---|---|---|---|
|
(same as x ) |
absolute value | abs(-17.4) |
17.4 |
|
dp |
cube root | cbrt(27.0) |
3 |
|
(same as input) | smallest integer not less than argument | ceil(-42.8) |
-42 |
|
(same as input) | smallest integer not less than argument (alias for ceil ) |
ceiling(-95.3) |
-95 |
|
dp |
radians to degrees | degrees(0.5) |
28.6478897565412 |
|
(same as input) | exponential | exp(1.0) |
2.71828182845905 |
|
(same as input) | largest integer not greater than argument | floor(-42.8) |
-43 |
|
(same as input) | natural logarithm | ln(2.0) |
0.693147180559945 |
|
(same as input) | base 10 logarithm | log(100.0) |
2 |
|
numeric |
logarithm to base b
|
log(2.0, 64.0) |
6.0000000000 |
|
(same as argument types) | remainder of y /x
|
mod(9,4) |
1 |
|
dp |
“π” constant | pi() |
3.14159265358979 |
|
dp |
a raised to the power of b
|
power(9.0, 3.0) |
729 |
|
numeric |
a raised to the power of b
|
power(9.0, 3.0) |
729 |
|
dp |
degrees to radians | radians(45.0) |
0.785398163397448 |
|
dp |
random value between 0.0 and 1.0 | random() |
|
|
(same as input) | round to nearest integer | round(42.4) |
42 |
|
numeric |
round to s decimal places |
round(42.4382, 2) |
42.44 |
|
int |
set seed for subsequent random() calls (value between 0 and 1.0) |
setseed(0.54823) |
1177314959 |
|
(same as input) | sign of the argument (-1, 0, +1) | sign(-8.4) |
-1 |
|
(same as input) | square root | sqrt(2.0) |
1.4142135623731 |
|
(same as input) | truncate toward zero | trunc(42.8) |
42 |
|
numeric |
truncate to s decimal places |
trunc(42.4382, 2) |
42.43 |
|
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 |
Finally, Table 9.4, “Trigonometric Functions” shows the
available trigonometric functions. All trigonometric functions
take arguments and return values of type double
precision
.
Table 9.4. Trigonometric Functions
Function | Description |
---|---|
|
inverse cosine |
|
inverse sine |
|
inverse tangent |
|
inverse tangent of
|
|
cosine |
|
cotangent |
|
sine |
|
tangent |