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# Comparison functions
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Timestream for LiveAnalytics supports the following comparison functions.

**Topics**
+ [greatest()](comparison-functions.greatest.md)
+ [least()](comparison-functions.least.md)
+ [ALL(), ANY() and SOME()](comparison-functions.all-any-some.md)

# greatest()
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The **greatest()** function returns the largest of the provided values. It returns `NULL` if any of the provided values are `NULL`. The syntax is as follows.

```
greatest(value1, value2, ..., valueN) 
```

# least()
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The **least()** function returns the smallest of the provided values. It returns `NULL` if any of the provided values are `NULL`. The syntax is as follows.

```
least(value1, value2, ..., valueN) 
```

# ALL(), ANY() and SOME()
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The `ALL`, `ANY` and `SOME` quantifiers can be used together with comparison operators in the following way.


| Expression | Meaning | 
| --- | --- | 
|  A = ALL(...)  |  Evaluates to true when A is equal to all values.  | 
|  A <> ALL(...)  |  Evaluates to true when A does not match any value.  | 
|  A < ALL(...)  |  Evaluates to true when A is smaller than the smallest value.  | 
|  A = ANY(...)  |  Evaluates to true when A is equal to any of the values.   | 
|  A <> ANY(...)  |  Evaluates to true when A does not match one or more values.  | 
|  A < ANY(...)  |  Evaluates to true when A is smaller than the biggest value.  | 

## Examples and usage notes
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**Note**  
When using `ALL`, `ANY` or `SOME`, the keyword `VALUES` should be used if the comparison values are a list of literals. 

## Example: `ANY()`
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An example of `ANY()` in a query statement as follows.

```
SELECT 11.7 = ANY (VALUES 12.0, 13.5, 11.7)
```

An alternative syntax for the same operation is as follows.

```
SELECT 11.7 = ANY (SELECT 12.0 UNION ALL SELECT 13.5 UNION ALL SELECT 11.7)
```

In this case, `ANY()` evaluates to `True`.

## Example: `ALL()`
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An example of `ALL()` in a query statement as follows.

```
SELECT 17 < ALL (VALUES 19, 20, 15);
```

An alternative syntax for the same operation is as follows.

```
SELECT 17 < ALL (SELECT 19 UNION ALL SELECT 20 UNION ALL SELECT 15);
```

In this case, `ALL()` evaluates to `False`.

## Example: `SOME()`
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An example of `SOME()` in a query statement as follows.

```
SELECT 50 >= SOME (VALUES 53, 77, 27);
```

An alternative syntax for the same operation is as follows.

```
SELECT 50 >= SOME (SELECT 53 UNION ALL SELECT 77 UNION ALL SELECT 27);
```

In this case, `SOME()` evaluates to `True`.