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# SQL ISNULL Functions

### SQL ISNULL()

Look at the following "Products" table:

![](https://826093633-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LS8lPNzCGPR5-DLbGXv%2F-LScEsBM_b-6qP2URXfh%2F-LScFA0jDpstu7EFW17_%2Fimage.png?alt=media\&token=a0b58534-ea51-40fb-9968-7cb6c558266c)

\
Suppose that the "UnitsOnOrder" column is optional, and may contain NULL values.

Look at the following SELECT statement:

```sql
SELECT ProductName, UnitPrice * (UnitsInStock + UnitsOnOrder)
FROM Products;
```

In the example above, if any of the "UnitsOnOrder" values are NULL, the result will be NULL.

### Example

The SQL Server [ISNULL()](https://www.w3schools.com/sql/func_sqlserver_isnull.asp) function lets you return an alternative value when an expression is NULL:<br>

```sql
SELECT ProductName, UnitPrice * (UnitsInStock + ISNULL(UnitsOnOrder, 0))
FROM Products
```