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 4-2. Mathematical Operators
| Name | 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 |
| & | Binary AND | 91 & 15 | 11 |
| | | Binary OR | 32 | 3 | 35 |
| # | Binary XOR | 17 # 5 | 20 |
| ~ | Binary NOT | ~1 | -2 |
| << | Binary shift left | 1 << 4 | 16 |
| >> | Binary shift right | 8 >> 2 | 2 |
The "binary" operators are also available for the bit string types BIT and BIT VARYING.
Table 4-3. Bit String Binary Operators
| Example | Result |
|---|---|
| B'10001' & B'01101' | 00001 |
| B'10001' | B'01101' | 11101 |
| B'10001' # B'01101' | 11110 |
| ~ B'10001' | 01110 |
| B'10001' << 3 | 01000 |
| B'10001' >> 2 | 00100 |
Table 4-4. Mathematical Functions
| Function | Return Type | Description | Example | Result |
|---|---|---|---|---|
abs(x) |
(same as x) | absolute value | abs(-17.4) | 17.4 |
cbrt(dp) |
dp | cube root | cbrt(27.0) | 3 |
ceil(numeric) |
numeric | smallest integer not less than argument | ceil(-42.8) | -42 |
degrees(dp) |
dp | radians to degrees | degrees(0.5) | 28.6478897565412 |
exp(dp) |
dp | exponential | exp(1.0) | 2.71828182845905 |
floor(numeric) |
numeric | largest integer not greater than argument | floor(-42.8) | -43 |
ln(dp) |
dp | natural logarithm | ln(2.0) | 0.693147180559945 |
log(dp) |
dp | base 10 logarithm | log(100.0) | 2 |
log(b numeric,
x numeric) |
numeric | logarithm to base b |
log(2.0, 64.0) | 6.0000000000 |
mod(y, x) |
(same as argument types) | remainder of y/x |
mod(9,4) | 1 |
pi() |
dp | "Pi" constant | pi() | 3.14159265358979 |
pow(e dp,
n dp) |
dp | raise a number to exponent e |
pow(9.0, 3.0) | 729 |
radians(dp) |
dp | degrees to radians | radians(45.0) | 0.785398163397448 |
random() |
dp | value between 0.0 to 1.0 | random() | |
round(dp) |
dp | round to nearest integer | round(42.4) | 42 |
round(v numeric,
s integer) |
numeric | round to s decimal
places |
round(42.4382, 2) | 42.44 |
sign(numeric) |
numeric | sign of the argument (-1, 0, +1) | sign(-8.4) | -1 |
sqrt(dp) |
dp | square root | sqrt(2.0) | 1.4142135623731 |
trunc(dp) |
dp | truncate toward zero | trunc(42.8) | 42 |
trunc(numeric, s
integer) |
numeric | truncate to s decimal
places |
trunc(42.4382, 2) | 42.43 |
In the table above, dp indicates
double precision. The functions
exp, ln, log,
pow, round (1 argument), sqrt, and trunc
(1 argument) are also available for the type numeric in place of double
precision. Functions returning a numeric result take numeric
input arguments, unless otherwise specified. Many of these
functions are implemented on top of the host system's C library;
accuracy and behavior in boundary cases could therefore vary
depending on the host system.
Table 4-5. Trigonometric Functions
| Function | Description |
|---|---|
acos(x) |
inverse cosine |
asin(x) |
inverse sine |
atan(x) |
inverse tangent |
atan2(x, y) |
inverse tangent of y/x |
cos(x) |
cosine |
cot(x) |
cotangent |
sin(x) |
sine |
tan(x) |
tangent |
All trigonometric functions have arguments and return values of type double precision.