The IsNull() function checks whether an expression contains Null (no data). This function returns a Boolean value. TRUE (-1) indicates that the expression is a Null value, and. Ważne: Użyj funkcji IsNull, aby sprawdzić, czy wyrażenie zawiera wartość null.
Wynika to z faktu, że dowolne wyrażenie zawierające Nełny jest równe null, a więc Fałsz. The IsNull function returns TRUE if the expression is a null value. The table above named Borrow Table in Library Database.
Access Database and Templates. You can see that the ReturnDate field has the null value, meaning that the book is still borrowed and has not returned yet. If expression consists of more than one variable, Null in any constituent variable causes True to be returned for the entire expression. You would use Is Null and Is Not Null in query expressions and SQL WHERE clauses. Iff i switch to nie jest standar więc nie wiem dlaczego ich stosowanie ma być lepsze od NZ.

Replaces NULL with the specified replacement value. IsNull (), on the other han is a Visual Basic. NZ ma odpowiednik w innych bazach, a IIF nie. Others have pointed out the functional difference. This SQL Server tutorial explains how to use the ISNULL function in SQL Server (Transact- SQL ) with syntax and examples.
The SQL ISNULL function enables you replacing the NULL values with the specified value as retrieving data from the SQL Server database.
