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.NET Forum / Windows Forms / WinForm General / December 2004Detecting SQL Null values
When a sql column is read that contains a null, how is that detected. A sql null value does not appear to be a system.dbnull.value. What data type is used to detect the presence of a sql null. Thanks, Fred Herring "Fred Herring" <FredHerring@discussions.microsoft.com> schrieb: > When a sql column is read that contains a null, how is that detected. A > sql > null value does not appear to be a system.dbnull.value. What data type is > used to detect the presence of a sql null. Depending on the datatype, you can compare with 'Sql<datatype>.Null'.  SignatureM S Herfried K. Wagner M V P <URL:http://dotnet.mvps.org/> V B <URL:http://dotnet.mvps.org/dotnet/faqs/ Or get another solution from SQL query: SELECT CASE WHEN (Field1 IS NULL) THEN '' ELSE Field1 END AS Field1, CASE WHEN (Field2 IS NULL) THEN 0 ELSE Field2 END AS Field2 FROM myTable --Field1 data type is nvarchar --Field2 data type is numeric So "null value does not appear in your codes. > "Fred Herring" <FredHerring@discussions.microsoft.com> schrieb: > > When a sql column is read that contains a null, how is that detected. A [quoted text clipped - 3 lines] > > Depending on the datatype, you can compare with 'Sql<datatype>.Null'. Or use COALESCE Select COALESCE(Field1,'') as Field1, COALESCE(Field2,0) as Field2 FROM myTable From the BOL: COALESCE Returns the first nonnull expression among its arguments COALESCE(expression1,...n) is equivalent to this CASE function: CASE WHEN (expression1 IS NOT NULL) THEN expression1 ... WHEN (expressionN IS NOT NULL) THEN expressionN ELSE NULL > Or get another solution from SQL query: > SELECT [quoted text clipped - 14 lines] >> >> Depending on the datatype, you can compare with 'Sql<datatype>.Null'. Is you use IsDBNull(field) it should return the results correctly for you... > When a sql column is read that contains a null, how is that detected. A > sql [quoted text clipped - 3 lines] > Thanks, > Fred Herring
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