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21 paź 2010 · SELECT ISNULL(NULLIF(primaryValue,0),secondaryValue) as Value FROM SomeTable. Here the NULLIF will return primaryValue as NULL only if it is already NULL or if it is 0. The ISNULL will return secondaryValue if primaryValue is NULL. Thus, if primaryValue is NULL or 0, then it will return secondaryValue.
The SQL Server ISNULL() function lets you return an alternative value when an expression is NULL: SELECT ProductName, UnitPrice * (UnitsInStock + ISNULL(UnitsOnOrder, 0)) FROM Products;
When you want to replace a possibly null column with something else, use IsNull. SELECT ISNULL(myColumn, 0 ) FROM myTable This will put a 0 in myColumn if it is null in the first place.
6 cze 2024 · The ISNULL function in MS SQL takes two arguments: the first is a value or column name, and the second is the default value if the first argument is null. This query retrieves rows where the code column is either null, an empty string, or contains only spaces.
3 wrz 2024 · The following example uses ISNULL to test for NULL values in the column MinPaymentAmount and display the value 0.00 for those rows. -- Uses AdventureWorks SELECT ResellerName, ISNULL(MinPaymentAmount,0) AS MinimumPayment FROM dbo.DimReseller ORDER BY ResellerName;
A NULL value is a special marker in column to denote that a value does not exist. It is important to understand that a NULL column value is different than having a blank (empty string) or 0 value in a column. eg. ' ' or (empty string) <> NULL, 0 <> NULL.
The IS NULL operator is used in a logical expression with the WHERE clause when we need to evaluate and determine whether a column value is NULL or not. The converse logic applies for the IS NOT NULL operator.
