# VAR\$1SAMP and VAR\$1POP functions
<a name="VARIANCE_functions"></a>

 The VAR\$1SAMP and VAR\$1POP functions return the sample and population variance of a set of numeric values (integer, decimal, or floating-point). The result of the VAR\$1SAMP function is equivalent to the squared sample standard deviation of the same set of values. 

VAR\$1SAMP and VARIANCE are synonyms for the same function. 

## Syntax
<a name="VARIANCE_functions-syntax"></a>

```
VAR_SAMP | VARIANCE ( [ DISTINCT | ALL ] expression)
VAR_POP ( [ DISTINCT | ALL ] expression)
```

The expression must have an integer, decimal, or floating-point data type. Regardless of the data type of the expression, the return type of this function is a double precision number. 

**Note**  
The results of these functions might vary across data warehouse clusters, depending on the configuration of the cluster in each case. 

## Usage notes
<a name="VARIANCE_usage_notes"></a>

When the sample variance (VARIANCE or VAR\$1SAMP) is calculated for an expression that consists of a single value, the result of the function is NULL not 0. 

## Examples
<a name="VARIANCE_functions-examples"></a>

The following query returns the rounded sample and population variance of the NUMTICKETS column in the LISTING table. 

```
select avg(numtickets),
round(var_samp(numtickets)) varsamp,
round(var_pop(numtickets)) varpop
from listing;

avg | varsamp | varpop
-----+---------+--------
10 |      54 |     54
(1 row)
```

The following query runs the same calculations but casts the results to decimal values. 

```
select avg(numtickets),
cast(var_samp(numtickets) as dec(10,4)) varsamp,
cast(var_pop(numtickets) as dec(10,4)) varpop
from listing;

avg | varsamp | varpop
-----+---------+---------
10 | 53.6291 | 53.6288
(1 row)
```