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194 lines
5.6 KiB
Markdown
194 lines
5.6 KiB
Markdown
---
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slug: /en/sql-reference/functions/logical-functions
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sidebar_position: 110
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sidebar_label: Logical
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---
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# Logical Functions
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Below functions perform logical operations on arguments of arbitrary numeric types. They return either 0 or 1 as [UInt8](../../sql-reference/data-types/int-uint.md) or in some cases `NULL`.
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Zero as an argument is considered `false`, non-zero values are considered `true`.
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## and
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Calculates the logical conjunction of two or more values.
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Setting [short_circuit_function_evaluation](../../operations/settings/settings.md#short-circuit-function-evaluation) controls whether short-circuit evaluation is used. If enabled, `val_i` is evaluated only if `(val_1 AND val_2 AND ... AND val_{i-1})` is `true`. For example, with short-circuit evaluation, no division-by-zero exception is thrown when executing the query `SELECT and(number = 2, intDiv(1, number)) FROM numbers(5)`.
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**Syntax**
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``` sql
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and(val1, val2...)
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```
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Alias: The [AND operator](../../sql-reference/operators/index.md#logical-and-operator).
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**Arguments**
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- `val1, val2, ...` — List of at least two values. [Int](../../sql-reference/data-types/int-uint.md), [UInt](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Nullable](../../sql-reference/data-types/nullable.md).
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**Returned value**
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- `0`, if at least one argument evaluates to `false`,
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- `NULL`, if no argument evaluates to `false` and at least one argument is `NULL`,
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- `1`, otherwise.
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Type: [UInt8](../../sql-reference/data-types/int-uint.md) or [Nullable](../../sql-reference/data-types/nullable.md)([UInt8](../../sql-reference/data-types/int-uint.md)).
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**Example**
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``` sql
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SELECT and(0, 1, -2);
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```
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Result:
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``` text
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┌─and(0, 1, -2)─┐
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│ 0 │
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└───────────────┘
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```
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With `NULL`:
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``` sql
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SELECT and(NULL, 1, 10, -2);
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```
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Result:
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``` text
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┌─and(NULL, 1, 10, -2)─┐
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│ ᴺᵁᴸᴸ │
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└──────────────────────┘
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```
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## or
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Calculates the logical disjunction of two or more values.
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Setting [short_circuit_function_evaluation](../../operations/settings/settings.md#short-circuit-function-evaluation) controls whether short-circuit evaluation is used. If enabled, `val_i` is evaluated only if `((NOT val_1) AND (NOT val_2) AND ... AND (NOT val_{i-1}))` is `true`. For example, with short-circuit evaluation, no division-by-zero exception is thrown when executing the query `SELECT or(number = 0, intDiv(1, number) != 0) FROM numbers(5)`.
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**Syntax**
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``` sql
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or(val1, val2...)
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```
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Alias: The [OR operator](../../sql-reference/operators/index.md#logical-or-operator).
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**Arguments**
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- `val1, val2, ...` — List of at least two values. [Int](../../sql-reference/data-types/int-uint.md), [UInt](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Nullable](../../sql-reference/data-types/nullable.md).
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**Returned value**
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- `1`, if at least one argument evaluates to `true`,
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- `0`, if all arguments evaluate to `false`,
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- `NULL`, if all arguments evaluate to `false` and at least one argument is `NULL`.
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Type: [UInt8](../../sql-reference/data-types/int-uint.md) or [Nullable](../../sql-reference/data-types/nullable.md)([UInt8](../../sql-reference/data-types/int-uint.md)).
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**Example**
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``` sql
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SELECT or(1, 0, 0, 2, NULL);
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```
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Result:
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``` text
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┌─or(1, 0, 0, 2, NULL)─┐
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│ 1 │
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└──────────────────────┘
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```
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With `NULL`:
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``` sql
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SELECT or(0, NULL);
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```
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Result:
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``` text
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┌─or(0, NULL)─┐
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│ ᴺᵁᴸᴸ │
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└─────────────┘
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```
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## not
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Calculates the logical negation of a value.
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**Syntax**
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``` sql
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not(val);
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```
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Alias: The [Negation operator](../../sql-reference/operators/index.md#logical-negation-operator).
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**Arguments**
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- `val` — The value. [Int](../../sql-reference/data-types/int-uint.md), [UInt](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Nullable](../../sql-reference/data-types/nullable.md).
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**Returned value**
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- `1`, if `val` evaluates to `false`,
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- `0`, if `val` evaluates to `true`,
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- `NULL`, if `val` is `NULL`.
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Type: [UInt8](../../sql-reference/data-types/int-uint.md) or [Nullable](../../sql-reference/data-types/nullable.md)([UInt8](../../sql-reference/data-types/int-uint.md)).
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**Example**
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``` sql
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SELECT NOT(1);
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```
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Result:
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``` test
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┌─not(1)─┐
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│ 0 │
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└────────┘
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```
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## xor
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Calculates the logical exclusive disjunction of two or more values. For more than two input values, the function first xor-s the first two values, then xor-s the result with the third value etc.
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**Syntax**
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``` sql
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xor(val1, val2...)
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```
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**Arguments**
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- `val1, val2, ...` — List of at least two values. [Int](../../sql-reference/data-types/int-uint.md), [UInt](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Nullable](../../sql-reference/data-types/nullable.md).
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**Returned value**
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- `1`, for two values: if one of the values evaluates to `false` and other does not,
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- `0`, for two values: if both values evaluate to `false` or to both `true`,
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- `NULL`, if at least one of the inputs is `NULL`
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Type: [UInt8](../../sql-reference/data-types/int-uint.md) or [Nullable](../../sql-reference/data-types/nullable.md)([UInt8](../../sql-reference/data-types/int-uint.md)).
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**Example**
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``` sql
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SELECT xor(0, 1, 1);
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```
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Result:
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``` text
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┌─xor(0, 1, 1)─┐
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│ 0 │
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└──────────────┘
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```
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