SQL IsNull (Oracle,mysql,mssql)

SQL IsNull (oracle,mysql tutorial, MSSQL)

IsNull
Replaces null with the specified replacement value.

Grammar
IsNull (Check_expression, Replacement_value)

Parameters
Check_expression

An expression that will be checked for null. Check_expression can be of any type.

Replacement_value

An expression to be returned when check_expression is null. Replacement_value must be with

Check_expresssion has the same type.

return type
Returns the same type as check_expression.

Comments
Returns the value of the expression if check_expression is not null;

Replacement_value

Example
A. Use ISNULL with Avg
The following example finds the average price of all books and replaces the values in the $10.00 of the titles table with the

All null entries.

Use pubs
Go
Select AVG (IsNull (price, $10.00))
From titles
Go

Let's take a look at other database tutorials

Oracle
Oracle has no IsNull () function. However, we can use the NVL () function to achieve the same result:

Select Productname,unitprice* (UNITSINSTOCK+NVL (unitsonorder,0))
From Products
Mysql
MySQL also has functions similar to IsNull (). But the way it works with Microsoft's IsNull () function

A little different.

In MySQL, we can use the ifnull () function, just like this:

Select Productname,unitprice* (Unitsinstock+ifnull (unitsonorder,0))
From Products