The **SQL SIGN function** is a mathematical function that is used to determine the sign of a numeric expression. The function returns a value of -1, 0, or 1, depending on whether the input expression is negative, zero, or positive, respectively.

## Syntax

The syntax of the **SIGN** function is as follows:

SIGN(numeric_expression)

Here, numeric_expression is the expression whose sign needs to be determined.

The **SIGN** function can be used with any numeric data type such as INT, BIGINT, FLOAT, DECIMAL, etc.

### Example

Let’s consider an example to better understand the usage of the SIGN function:

SELECT SIGN(-10) AS result;

In this example, the **SIGN** function is applied to the numeric value -10. Since the value is negative, the function returns -1 as the result. Therefore, the output of the above SQL statement would be: -1.

Similarly, we can apply the **SIGN function** to positive and zero values as well:

SELECT SIGN(20) AS result;

In this case, the value 20 is positive, so the function returns 1 as the result: 1.

SELECT SIGN(0) AS result;

In this case, the value 0 is neither positive nor negative, so the function returns 0 as the result: 0.

In conclusion, the **SIGN function** is a useful mathematical function in SQL that can be used to determine the sign of a numeric expression. It is particularly useful in applications where we need to distinguish between positive, negative, and zero values.