POWedit
Returns the value of a base (first argument) raised to the power of an exponent (second argument). Both arguments must be numeric.
ROW base = 2.0, exponent = 2 | EVAL result = POW(base, exponent)
| base:double | exponent:integer | result:double |
|---|---|---|
2.0 |
2 |
4.0 |
Type rulesedit
The type of the returned value is determined by the types of the base and exponent. The following rules are applied to determine the result type:
- If either of the base or exponent are of a floating point type, the result will be a double
- Otherwise, if either the base or the exponent are 64-bit (long or unsigned long), the result will be a long
- Otherwise, the result will be a 32-bit integer (this covers all other numeric types, including int, short and byte)
For example, using simple integers as arguments will lead to an integer result:
ROW base = 2, exponent = 2 | EVAL s = POW(base, exponent)
| base:integer | exponent:integer | s:integer |
|---|---|---|
2 |
2 |
4 |
The actual power function is performed using double precision values for all cases. This means that for very large non-floating point values there is a small chance that the operation can lead to slightly different answers than expected. However, a more likely outcome of very large non-floating point values is numerical overflow.
Arithmetic errorsedit
Arithmetic errors and numeric overflow do not result in an error. Instead, the result will be null
and a warning for the ArithmeticException added.
For example:
ROW x = POW(9223372036854775808, 2)
| warning:Line 1:9: evaluation of [POW(9223372036854775808, 2)] failed, treating result as null. Only first 20 failures recorded. |
|---|
warning:java.lang.ArithmeticException: long overflow |
| x:long |
|---|
null |
If it is desired to protect against numerical overruns, use TO_DOUBLE on either of the arguments:
ROW x = POW(9223372036854775808, TO_DOUBLE(1))
| x:double |
|---|
9.223372036854776E18 |
Fractional exponentsedit
The exponent can be a fraction, which is similar to performing a root.
For example, the exponent of 0.5 will give the square root of the base:
ROW base = 4, exponent = 0.5 | EVAL s = POW(base, exponent)
| base:integer | exponent:double | s:double |
|---|---|---|
4 |
0.5 |
2.0 |
Table of supported input and output typesedit
For clarity, the following table describes the output result type for all combinations of numeric input types:
| base | exponent | result |
|---|---|---|
double |
double |
double |
double |
integer |
double |
integer |
double |
double |
integer |
integer |
integer |
long |
double |
double |
long |
integer |
long |