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.