mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-12-20 05:05:38 +00:00
253 lines
5.0 KiB
Markdown
253 lines
5.0 KiB
Markdown
---
|
||
toc_priority: 48
|
||
toc_title: Bit
|
||
---
|
||
|
||
# Bit functions {#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) {#bitanda-b}
|
||
|
||
## bitOr(a, b) {#bitora-b}
|
||
|
||
## bitXor(a, b) {#bitxora-b}
|
||
|
||
## bitNot(a) {#bitnota}
|
||
|
||
## bitShiftLeft(a, b) {#bitshiftlefta-b}
|
||
|
||
## bitShiftRight(a, b) {#bitshiftrighta-b}
|
||
|
||
## bitRotateLeft(a, b) {#bitrotatelefta-b}
|
||
|
||
## bitRotateRight(a, b) {#bitrotaterighta-b}
|
||
|
||
## bitTest {#bittest}
|
||
|
||
Takes any integer and converts it into [binary form](https://en.wikipedia.org/wiki/Binary_number), returns the value of a bit at specified position. The countdown starts from 0 from the right to the left.
|
||
|
||
**Syntax**
|
||
|
||
``` sql
|
||
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:
|
||
|
||
``` sql
|
||
SELECT bitTest(43, 1)
|
||
```
|
||
|
||
Result:
|
||
|
||
``` text
|
||
┌─bitTest(43, 1)─┐
|
||
│ 1 │
|
||
└────────────────┘
|
||
```
|
||
|
||
Another example:
|
||
|
||
Query:
|
||
|
||
``` sql
|
||
SELECT bitTest(43, 2)
|
||
```
|
||
|
||
Result:
|
||
|
||
``` text
|
||
┌─bitTest(43, 2)─┐
|
||
│ 0 │
|
||
└────────────────┘
|
||
```
|
||
|
||
## bitTestAll {#bittestall}
|
||
|
||
Returns result of [logical conjuction](https://en.wikipedia.org/wiki/Logical_conjunction) (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**
|
||
|
||
``` sql
|
||
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:
|
||
|
||
``` sql
|
||
SELECT bitTestAll(43, 0, 1, 3, 5)
|
||
```
|
||
|
||
Result:
|
||
|
||
``` text
|
||
┌─bitTestAll(43, 0, 1, 3, 5)─┐
|
||
│ 1 │
|
||
└────────────────────────────┘
|
||
```
|
||
|
||
Another example:
|
||
|
||
Query:
|
||
|
||
``` sql
|
||
SELECT bitTestAll(43, 0, 1, 3, 5, 2)
|
||
```
|
||
|
||
Result:
|
||
|
||
``` text
|
||
┌─bitTestAll(43, 0, 1, 3, 5, 2)─┐
|
||
│ 0 │
|
||
└───────────────────────────────┘
|
||
```
|
||
|
||
## bitTestAny {#bittestany}
|
||
|
||
Returns result of [logical disjunction](https://en.wikipedia.org/wiki/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**
|
||
|
||
``` sql
|
||
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:
|
||
|
||
``` sql
|
||
SELECT bitTestAny(43, 0, 2)
|
||
```
|
||
|
||
Result:
|
||
|
||
``` text
|
||
┌─bitTestAny(43, 0, 2)─┐
|
||
│ 1 │
|
||
└──────────────────────┘
|
||
```
|
||
|
||
Another example:
|
||
|
||
Query:
|
||
|
||
``` sql
|
||
SELECT bitTestAny(43, 4, 2)
|
||
```
|
||
|
||
Result:
|
||
|
||
``` text
|
||
┌─bitTestAny(43, 4, 2)─┐
|
||
│ 0 │
|
||
└──────────────────────┘
|
||
```
|
||
## bitCount {#bitcount}
|
||
|
||
Calculates the number of bits set to one in the binary representation of a number.
|
||
|
||
**Syntax**
|
||
|
||
```sql
|
||
bitCount(x)
|
||
```
|
||
|
||
**Parameters**
|
||
|
||
- `x` — [Integer](../../sql_reference/data_types/int_uint.md) or [floating-point](../../sql_reference/data_types/float.md) 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](https://en.wikipedia.org/wiki/Sign_extension)). So, for example, `bitCount(toUInt8(-1)) = 8`.
|
||
|
||
Type: `UInt8`.
|
||
|
||
**Example**
|
||
|
||
Take for example the number 333. Its binary representation: 0000000101001101.
|
||
|
||
Query:
|
||
|
||
```sql
|
||
SELECT bitCount(333)
|
||
```
|
||
|
||
Result:
|
||
|
||
```text
|
||
┌─bitCount(333)─┐
|
||
│ 5 │
|
||
└───────────────┘
|
||
```
|
||
|
||
[Original article](https://clickhouse.tech/docs/en/query_language/functions/bit_functions/) <!--hide-->
|