Numeric functions

This page describes the available functions to assist with performing numeric calculations.

abs

abs(value) return the absolute value. The behavior of abs is as follows:

When the input value is positive, abs returns value
When the input value is negative, abs returns - value
When the input value is 0, abs returns 0

Arguments:

value is any numeric value.

Return value:

Return value type is the same as the type of the argument.

Examples:

SELECT
    x - 2 a,
    abs(x -2)
FROM long_sequence(3);

a	abs
-1	1
0	0
1	1

ceil / ceiling

ceil(value) or ceiling() returns the smallest integer greater than, or equal to, a specified numeric expression.

Arguments:

value is any numeric value.

Return value:

Return value type is double.

Examples:

SELECT ceil(15.75) as RoundedUp;

RoundedUp
16

exp

exp() returns the exponential value of a specified numeric expression.

Arguments:

value is any numeric value.

Return value:

Return value type is double.

Examples:

SELECT exp(2) as Exponent;

Exponent
7.38905609893

floor

floor() returns the largest integer less than or equal to a specified numeric expression.

Arguments:

value is any numeric value.

Return value:

Return value type is double.

Examples:

SELECT floor(15.75) as RoundedDown;

RoundedUp
15

ln

ln(value) return the natural logarithm (loge) of a given number.

Arguments:

value is any numeric value.

Return value:

Return value type is double.

Examples:

SELECT ln(4.123)

ln
1.416581053724

log

log(value) return the base 10 logarithm of a given number.

Arguments:

value is any numeric value.

Return value:

Return value type is double.

Examples:

SELECT log(100)

log
2

note

Some databases use LOG to refer to the natural logarithm and LOG10 for the base 10 logarithm. QuestDB follows PostgreSQL conventions and uses LOG for base 10 and LN for natural logarithm.

power

power(base, exponent) returns the value of a number base raised to the power defined by exponent.

Arguments:

base is any numeric value.
exponent is any numeric value.

Return value:

Return value type is double.

Examples:

SELECT power(2, 3);

power
8

round

round(value, scale) returns the closest value in the specified scale. It uses the "half up" tie-breaking method when the value is exactly halfway between the round_up and round_down values.

round(value) is equivalent to round(value, 0).

Arguments:

value is any numeric value.
scale is the number of decimal points returned. A negative scale means the rounding will occur to a digit to the left of the decimal point. For example, -1 means the number will be rounded to the nearest tens and +1 to the nearest tenths.

Return value:

Return value type is double.

Examples:

SELECT
    d,
    round(d, -2),
    round(d, -1),
    round(d,0),
    round(d,1),
    round(d,2)
FROM dbl;

d	round-2	round-1	round0	round1	round2
-0.811905406	0	0	-1	-0.8	-0.81
-5.002768547	0	-10	-5	-5	-5
-64.75487334	-100	-60	-65	-64.8	-64.75
-926.531695	-900	-930	-927	-926.5	-926.53
0.069361448	0	0	0	0.1	0.07
4.003627053	0	0	4	4	4
86.91359825	100	90	87	86.9	86.91
376.3807766	400	380	376	376.4	376.38

round_down

round_down(value, scale) - rounds a value down to the specified scale

Arguments:

value is any numeric value.
scale is the number of decimal points returned. A negative scale means the rounding will occur to a digit to the left of the decimal point. For example, -1 means the number will be rounded to the nearest tens and +1 to the nearest tenths.

Return value:

Return value type is double.

Examples:

SELECT
    d,
    round_down(d, -2),
    round_down(d, -1),
    round_down(d,0),
    round_down(d,1),
    round_down(d,2)
FROM dbl;

d	r_down-2	r_down-1	r_down0	r_down1	r_down2
-0.811905406	0	0	0	-0.8	-0.81
-5.002768547	0	0	-5	-5	-5
-64.75487334	0	-60	-64	-64.7	-64.75
-926.531695	-900	-920	-926	-926.5	-926.53
0.069361448	0	0	0	0	0.06
4.003627053	0	0	4	4	4
86.91359825	0	80	86	86.9	86.91
376.3807766	400	370	376	376.3	376.38

round_half_even

round_half_even(value, scale) - returns the closest value in the specified scale. It uses the "half up" tie-breaking method when the value is exactly halfway between the round_up and round_down values.

Arguments:

value is any numeric value.
scale is the number of decimal points returned. A negative scale means the rounding will occur to a digit to the left of the decimal point. For example, -1 means the number will be rounded to the nearest tens and +1 to the nearest tenths.

Return value:

Return value type is double.

Examples:

Tie-breaker behavior
SELECT
    round_half_even(5.55, 1),
    round_half_even(5.65, 1)
FROM long_sequence(1);

round_half_even	round_half_even
5.6	5.6

More examples
SELECT
    d,
    round_half_even(d, -2),
    round_half_even(d, -1),
    round_half_even(d,0),
    round_half_even(d,1),
    round_half_even(d,2)
FROM dbl;

d	r_h_e-2	r_h_e-1	r_h_e0	r_h_e1	r_h_e2
-0.811905406	0	0	-1	-0.8	-0.81
-5.002768547	0	0	-5	-5	-5
-64.75487334	-100	-60	-65	-64.8	-64.75
-926.531695	-900	-930	-927	-926.5	-926.53
0.069361448	0	0	0	0.1	0.07
4.003627053	0	0	4	4	4
86.91359825	100	90	87	86.9	86.91
376.3807766	400	380	376	376.4	376.38

round_up

round_up(value, scale) - rounds a value up to the specified scale

Arguments:

value is any numeric value.
scale is the number of decimal points returned. A negative scale means the rounding will occur to a digit to the left of the decimal point. For example, -1 means the number will be rounded to the nearest tens and +1 to the nearest tenths.

Return value:

Return value type is double.

Examples:

SELECT
    d,
    round_up(d, -2),
    round_up(d, -1),
    round_up(d,0),
    round_up(d,1),
    round_up(d,2)
FROM dbl;

d	r_up-2	r_up-1	r_up0	r_up1	r_up2
-0.811905406	-100	-10	-1	-0.9	-0.82
-5.002768547	-100	-10	-6	-5.1	-5.01
-64.75487334	-100	-70	-65	-64.8	-64.76
-926.531695	-1000	-930	-927	-926.6	-926.54
0.069361448	100	10	1	0.1	0.07
4.003627053	100	10	5	4.1	4.01
86.91359825	100	90	87	87	86.92
376.3807766	400	380	377	376.4	376.39

sign

sign(value) returns sign of the argument, that is:

-1 for negative value
0 for zero
+1 for positive value

Arguments:

value is any numeric value.

Return value:

Return value type is the same as argument's.

Examples:

SELECT x-3 arg, sign(x-3) from long_sequence(5)

arg	sign
-2	-1
-1	-1
0	0
1	1
2	1

size_pretty

size_pretty(value) returns a human-readable string equivalent to the input value.

Arguments:

value is a long value that represents size in bytes.

Return value:

Return value type is string. The string contains the size as a floating point with one significant figure followed by the scale in base 1024.

Examples:

SELECT size_pretty(400032);

size_pretty
390.7 KiB

sqrt

sqrt(value) return the square root of a given number.

Arguments:

value is any numeric value.

Return value:

Return value type is double.

Examples:

SELECT sqrt(4000.32)

log
63.2480829749013

abs​

ceil / ceiling​

exp​

floor​

ln​

log​

power​

round​

round_down​

round_half_even​

round_up​

sign​

size_pretty​

sqrt​

abs

ceil / ceiling

exp

floor

ln

log

power

round

round_down

round_half_even

round_up

sign

size_pretty

sqrt