5.0 KiB
| toc_priority | toc_title |
|---|---|
| 48 | Bit |
Bit functions
Bit functions work for any pair of types from UInt8, UInt16, UInt32, UInt64, Int8, Int16, Int32, Int64, Float32, or Float64.
The result type is an integer with bits equal to the maximum bits of its arguments. If at least one of the arguments is signed, the result is a signed number. If an argument is a floating-point number, it is cast to Int64.
bitAnd(a, b)
bitOr(a, b)
bitXor(a, b)
bitNot(a)
bitShiftLeft(a, b)
bitShiftRight(a, b)
bitRotateLeft(a, b)
bitRotateRight(a, b)
bitTest
Takes any integer and converts it into binary form, returns the value of a bit at specified position. The countdown starts from 0 from the right to the left.
Syntax
SELECT bitTest(number, index)
Parameters
number– integer number.index– position of bit.
Returned values
Returns a value of bit at specified position.
Type: UInt8.
Example
For example, the number 43 in base-2 (binary) numeral system is 101011.
Query:
SELECT bitTest(43, 1)
Result:
┌─bitTest(43, 1)─┐
│ 1 │
└────────────────┘
Another example:
Query:
SELECT bitTest(43, 2)
Result:
┌─bitTest(43, 2)─┐
│ 0 │
└────────────────┘
bitTestAll
Returns result of logical conjuction (AND operator) of all bits at given positions. The countdown starts from 0 from the right to the left.
The conjuction for bitwise operations:
0 AND 0 = 0
0 AND 1 = 0
1 AND 0 = 0
1 AND 1 = 1
Syntax
SELECT bitTestAll(number, index1, index2, index3, index4, ...)
Parameters
number– integer number.index1,index2,index3,index4– positions of bit. For example, for set of positions (index1,index2,index3,index4) is true if and only if all of its positions are true (index1⋀index2, ⋀index3⋀index4).
Returned values
Returns result of logical conjuction.
Type: UInt8.
Example
For example, the number 43 in base-2 (binary) numeral system is 101011.
Query:
SELECT bitTestAll(43, 0, 1, 3, 5)
Result:
┌─bitTestAll(43, 0, 1, 3, 5)─┐
│ 1 │
└────────────────────────────┘
Another example:
Query:
SELECT bitTestAll(43, 0, 1, 3, 5, 2)
Result:
┌─bitTestAll(43, 0, 1, 3, 5, 2)─┐
│ 0 │
└───────────────────────────────┘
bitTestAny
Returns result of logical disjunction (OR operator) of all bits at given positions. The countdown starts from 0 from the right to the left.
The disjunction for bitwise operations:
0 OR 0 = 0
0 OR 1 = 1
1 OR 0 = 1
1 OR 1 = 1
Syntax
SELECT bitTestAny(number, index1, index2, index3, index4, ...)
Parameters
number– integer number.index1,index2,index3,index4– positions of bit.
Returned values
Returns result of logical disjuction.
Type: UInt8.
Example
For example, the number 43 in base-2 (binary) numeral system is 101011.
Query:
SELECT bitTestAny(43, 0, 2)
Result:
┌─bitTestAny(43, 0, 2)─┐
│ 1 │
└──────────────────────┘
Another example:
Query:
SELECT bitTestAny(43, 4, 2)
Result:
┌─bitTestAny(43, 4, 2)─┐
│ 0 │
└──────────────────────┘
bitCount
Calculates the number of bits set to one in the binary representation of a number.
Syntax
bitCount(x)
Parameters
x— Integer or floating-point number. The function uses the value representation in memory. It allows supporting floating-point numbers.
Returned value
- Number of bits set to one in the input number.
The function doesn't convert input value to a larger type (sign extension). So, for example, bitCount(toUInt8(-1)) = 8.
Type: UInt8.
Example
Take for example the number 333. Its binary representation: 0000000101001101.
Query:
SELECT bitCount(333)
Result:
┌─bitCount(333)─┐
│ 5 │
└───────────────┘