ClickHouse/docs/en/sql-reference/functions/arithmetic-functions.md
Robert Schulze bb0573cd56
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2023-04-19 18:11:50 +00:00

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/en/sql-reference/functions/arithmetic-functions 5 Arithmetic

Arithmetic Functions

The result type of all arithmetic functions is the smallest type which can represent all possible results. Size promotion happens for integers up to 32 bit, e.g. UInt8 + UInt16 = UInt32. If one of the inters has 64 or more bits, the result is of the same type as the bigger of the input integers, e.g. UInt16 + UInt128 = UInt128. While this introduces a risk of overflows around the value range boundary, it ensures that calculations are performed quickly using the maximum native integer width of 64 bit.

The result of addition or multiplication of two integers is unsigned unless one of the integers is signed.

Example:

SELECT toTypeName(0), toTypeName(0 + 0), toTypeName(0 + 0 + 0), toTypeName(0 + 0 + 0 + 0)
┌─toTypeName(0)─┬─toTypeName(plus(0, 0))─┬─toTypeName(plus(plus(0, 0), 0))─┬─toTypeName(plus(plus(plus(0, 0), 0), 0))─┐
│ UInt8         │ UInt16                 │ UInt32                          │ UInt64                                   │
└───────────────┴────────────────────────┴─────────────────────────────────┴──────────────────────────────────────────┘

Arithmetic functions work for any pair of UInt8, UInt16, UInt32, UInt64, Int8, Int16, Int32, Int64, Float32, or Float64 values.

Overflows are produced the same way as in C++.

plus

Calculates the sum of two values a and b.

Syntax

plus(a, b)

It is possible to add an integer and a date or date with time. The former operation increments the number of days in the date, the latter operation increments the number of seconds in the date with time.

Alias: a + b (operator)

minus

Calculates the difference of two values a and b. The result is always signed.

Similar to plus, it is possible to subtract an integer from a date or date with time.

Syntax

minus(a, b)

Alias: a - b (operator)

multiply

Calculates the product of two values a and b.

Syntax

multiply(a, b)

Alias: a \* b (operator)

divide

Calculates the quotient of two values a and b. The result is always a floating-point value. If you need integer division, you can use the intDiv function.

Division by 0 returns inf, -inf, or nan.

Syntax

divide(a, b)

Alias: a / b (operator)

intDiv

Performs an integer division of two values a by b, i.e. computes the quotient rounded down to the next smallest integer.

The result has the same type as the dividend (the first parameter).

An exception is thrown when dividing by zero, when the quotient does not fit in the range of the dividend, or when dividing a minimal negative number by minus one.

Syntax

intDiv(a, b)

Example

Query:

SELECT
    intDiv(toFloat64(1), 0.001) AS res,
    toTypeName(res)
┌──res─┬─toTypeName(intDiv(toFloat64(1), 0.001))─┐
│ 1000 │ Int64                                   │
└──────┴─────────────────────────────────────────┘
SELECT
    intDiv(1, 0.001) AS res,
    toTypeName(res)
Received exception from server (version 23.2.1):
Code: 153. DB::Exception: Received from localhost:9000. DB::Exception: Cannot perform integer division, because it will produce infinite or too large number: While processing intDiv(1, 0.001) AS res, toTypeName(res). (ILLEGAL_DIVISION)

intDivOrZero

Same as intDiv but returns zero when dividing by zero or when dividing a minimal negative number by minus one.

Syntax

intDivOrZero(a, b)

modulo

Calculates the remainder of the division of two values a by b.

The result type is an integer if both inputs are integers. If one of the inputs is a floating-point number, the result is a floating-point number.

The remainder is computed like in C++. Truncated division is used for negative numbers.

An exception is thrown when dividing by zero or when dividing a minimal negative number by minus one.

Syntax

modulo(a, b)

Alias: a % b (operator)

moduloOrZero

Like modulo but returns zero when the divisor is zero.

Syntax

moduloOrZero(a, b)

positiveModulo(a, b)

Like modulo but always returns a non-negative number.

This function is 4-5 times slower than modulo.

Syntax

positiveModulo(a, b)

Alias:

  • positive_modulo(a, b)
  • pmod(a, b)

Example

Query:

SELECT positiveModulo(-1, 10)

Result:

┌─positiveModulo(-1, 10)─┐
│                      9 │
└────────────────────────┘

negate

Negates a value a. The result is always signed.

Syntax

negate(a)

Alias: -a

abs

Calculates the absolute value of a. Has no effect if a is of an unsigned type. If a is of a signed type, it returns an unsigned number.

Syntax

abs(a)

gcd

Returns the greatest common divisor of two values a and b.

An exception is thrown when dividing by zero or when dividing a minimal negative number by minus one.

Syntax

gcd(a, b)

lcm(a, b)

Returns the least common multiple of two values a and b.

An exception is thrown when dividing by zero or when dividing a minimal negative number by minus one.

Syntax

lcm(a, b)

max2

Returns the bigger of two values a and b. The returned value is of type Float64.

Syntax

max2(a, b)

Example

Query:

SELECT max2(-1, 2);

Result:

┌─max2(-1, 2)─┐
│           2 │
└─────────────┘

min2

Returns the smaller of two values a and b. The returned value is of type Float64.

Syntax

min2(a, b)

Example

Query:

SELECT min2(-1, 2);

Result:

┌─min2(-1, 2)─┐
│          -1 │
└─────────────┘

multiplyDecimal

Multiplies two decimals a and b. The result value will be of type Decimal256.

The scale of the result can be explicitly specified by result_scale. If result_scale is not specified, it is assumed to be the maximum scale of the input values.

This function work significantly slower than usual multiply. In case no control over the result precision is needed and/or fast computation is desired, consider using multiply.

Syntax

multiplyDecimal(a, b[, result_scale])

Arguments

Returned value

  • The result of multiplication with given scale.

Type: Decimal256.

Example

┌─multiplyDecimal(toDecimal256(-12, 0), toDecimal32(-2.1, 1), 1)─┐
│                                                           25.2 │
└────────────────────────────────────────────────────────────────┘

Differences compared to regular multiplication:

SELECT toDecimal64(-12.647, 3) * toDecimal32(2.1239, 4);
SELECT toDecimal64(-12.647, 3) as a, toDecimal32(2.1239, 4) as b, multiplyDecimal(a, b);

Result:

┌─multiply(toDecimal64(-12.647, 3), toDecimal32(2.1239, 4))─┐
│                                               -26.8609633 │
└───────────────────────────────────────────────────────────┘
┌─multiplyDecimal(toDecimal64(-12.647, 3), toDecimal32(2.1239, 4))─┐
│                                                         -26.8609 │
└──────────────────────────────────────────────────────────────────┘
SELECT
    toDecimal64(-12.647987876, 9) AS a,
    toDecimal64(123.967645643, 9) AS b,
    multiplyDecimal(a, b);

SELECT
    toDecimal64(-12.647987876, 9) AS a,
    toDecimal64(123.967645643, 9) AS b,
    a * b;

Result:

┌─────────────a─┬─────────────b─┬─multiplyDecimal(toDecimal64(-12.647987876, 9), toDecimal64(123.967645643, 9))─┐
│ -12.647987876 │ 123.967645643 │                                                               -1567.941279108 │
└───────────────┴───────────────┴───────────────────────────────────────────────────────────────────────────────┘

Received exception from server (version 22.11.1):
Code: 407. DB::Exception: Received from localhost:9000. DB::Exception: Decimal math overflow: While processing toDecimal64(-12.647987876, 9) AS a, toDecimal64(123.967645643, 9) AS b, a * b. (DECIMAL_OVERFLOW)

divideDecimal

Divides two decimals a and b. The result value will be of type Decimal256.

The scale of the result can be explicitly specified by result_scale. If result_scale is not specified, it is assumed to be the maximum scale of the input values.

This function work significantly slower than usual divide. In case no control over the result precision is needed and/or fast computation is desired, consider using divide.

Syntax

divideDecimal(a, b[, result_scale])

Arguments

Returned value

  • The result of division with given scale.

Type: Decimal256.

Example

┌─divideDecimal(toDecimal256(-12, 0), toDecimal32(2.1, 1), 10)─┐
│                                                -5.7142857142 │
└──────────────────────────────────────────────────────────────┘

Differences compared to regular division:

SELECT toDecimal64(-12, 1) / toDecimal32(2.1, 1);
SELECT toDecimal64(-12, 1) as a, toDecimal32(2.1, 1) as b, divideDecimal(a, b, 1), divideDecimal(a, b, 5);

Result:

┌─divide(toDecimal64(-12, 1), toDecimal32(2.1, 1))─┐
│                                             -5.7 │
└──────────────────────────────────────────────────┘

┌───a─┬───b─┬─divideDecimal(toDecimal64(-12, 1), toDecimal32(2.1, 1), 1)─┬─divideDecimal(toDecimal64(-12, 1), toDecimal32(2.1, 1), 5)─┐
│ -12 │ 2.1 │                                                       -5.7 │                                                   -5.71428 │
└─────┴─────┴────────────────────────────────────────────────────────────┴────────────────────────────────────────────────────────────┘
SELECT toDecimal64(-12, 0) / toDecimal32(2.1, 1);
SELECT toDecimal64(-12, 0) as a, toDecimal32(2.1, 1) as b, divideDecimal(a, b, 1), divideDecimal(a, b, 5);

Result:

DB::Exception: Decimal result's scale is less than argument's one: While processing toDecimal64(-12, 0) / toDecimal32(2.1, 1). (ARGUMENT_OUT_OF_BOUND)

┌───a─┬───b─┬─divideDecimal(toDecimal64(-12, 0), toDecimal32(2.1, 1), 1)─┬─divideDecimal(toDecimal64(-12, 0), toDecimal32(2.1, 1), 5)─┐
│ -12 │ 2.1 │                                                       -5.7 │                                                   -5.71428 │
└─────┴─────┴────────────────────────────────────────────────────────────┴────────────────────────────────────────────────────────────┘