ExampleGet your own SQL Server Return the specified value IF the expression is NULL, otherwise return the expression: SELECT ISNULL(NULL, 'W3Schools.com'); Try it Yourself » Definition and UsageThe ISNULL() function returns a specified value if the expression is NULL....
The SQL Server ISNULL function returns the replacement value if the first parameterexpressionevaluates to NULL. SQL Server converts the data type of replacement to data type of expression. Let’s explore SQL ISNULL with examples. Example 1: SQL Server ISNULL function in an argument In this ex...
Applies to:SQL ServerAzure SQL DatabaseAzure SQL Managed Instance Creates a user-defined function (UDF), which is a Transact-SQL or common language runtime (CLR) routine. A user-defined function accepts parameters, performs an action such as a complex calculation, and returns the result of ...
The code samples in this article use theAdventureWorks2022orAdventureWorksDW2022sample database, which you can download from theMicrosoft SQL Server Samples and Community Projectshome page. A. Use ISNULL with AVG The following example finds the average of the weight of all products. It substitutes...
SQL Server The SQL ServerISNULL()function lets you return an alternative value when an expression is NULL: SELECTProductName, UnitPrice * (UnitsInStock + ISNULL(UnitsOnOrder,0)) FROMProducts; or we can use theCOALESCE()function, like this: ...
本文中的代码示例使用AdventureWorks2022或AdventureWorksDW2022示例数据库,可以从Microsoft SQL Server 示例和社区项目主页下载该数据库。 基本示例 以下示例特意进行了简化,以帮助您入门。 首先创建一个表以保存一些地理数据。 SQL CREATETABLEBasicDemo ( [Level] HIERARCHYIDNOTNULL, LocationNVARCHAR(30)NOTNULL, Location...
(See the SQL_DRIVER_HDESC or SQL_DRIVER_HSTMT descriptors later in this function description for more information.) If InfoValuePtr is NULL, StringLengthPtr will still return the total number of bytes (excluding the null-termination character for character data) available to return in the ...
In SQL Server, use IS NULL or IS NOT NULL. For example: SELECT … WHERE field IS NULL Convert null values with functions Use the null functions to protect your expressions and return alternative values: In Access, use the NZ (value, [valueifnull]) function which returns 0...
gsql:Oracle_Functions.sql:1035: NOTICE: | function | sys_guid() | 1.0 | sql | Skip due to version | gsql:Oracle_Functions.sql:1035: NOTICE: | aggregate | wm_concat(text) | 1.0 | internal | Skip due to version | gsql:Oracle_Functions.sql:1035: NOTICE: | function | nvl2(anyelem...
[Serializable] [Microsoft.SqlServer.Server.SqlUserDefinedType(Format.Native, IsByteOrdered=true)]publicstructPoint : INullable { ... } 实现可为 null 性 除了为您的程序集正确指定属性外,UDT 还必须支持为 Null 性。 加载到 SQL Server 中的 UDT 具有 null 感知性,但为了使 UDT 能够识别 null 值,UDT...