❮ Previous ❮ SQL Server Functions Next ❯ ExampleGet your own SQL Server Compare two expressions: SELECT NULLIF(25, 25); Try it Yourself » Definition and UsageThe NULLIF() function returns NULL if two expressions are equal, otherwise it returns the first expression....
sql server nullif 函数 sql null用法 目标:辨别并使用Null值 反模式:将Null值作为普通的值,反之亦然 1、在表达式中使用Null: Null值与空字符串是不一样的,Null值参与任何的加、减、乘、除等其他运算,结果都是Null; Null值与False也不同。And、Or和Not三个bool操作如果设计Null,结果很迷惑。 2、搜索运行为...
nullif(A,B)表示A和B是否相等,如果相等则返回null,否则返回A。 可以用于判断两值是否相等,或者除零错误。 a/nullif(b,0) 若b为0,则返回null
NULLIF is equivalent to a searched CASE expression in which the two expressions are equal and the resulting expression is NULL.We recommend that you not use time-dependent functions, such as RAND(), within a NULLIF function. This could cause the function to be evaluated twice and to return ...
NULLIF is equivalent to a searched CASE expression in which the two expressions are equal and the resulting expression is NULL. We recommend that you not use time-dependent functions, such as RAND(), within a NULLIF function. This could cause the function to be evaluated twice and to return...
Sql Server中两个判断是否为空的函数NULLIF和ISNULL的说明如下: NULLIF:需要两个参数,如果两个指定的表达式等价,则返回null 例子:NULLIF(a,b) 说明:如果a和b是相等的,那么返回NULL,如果不相等返回a select NULLIF('eqeqweqwe','1') 结果是eqeqweqwe ...
Sql Server中两个推断是否为空的函数NULLIF和ISNULL的说明例如以下: NULLIF:须要两个參数,假设两个指定的表达式等价,则返回null 样例:NULLIF(a,b) 说明:假设a和b是相等的,那么返回NULL,假设不相等返回a select NULLIF('eqeqweqwe','1') 结果是eqeqweqwe ...
SQL Server Management Studio 方法/步骤 1 1、ISNULL函数，判断参数是否为NULL函数格式：ISNULL(Expression1，Expression2)给定两个参数，如果Expression1是NULL，那么返回Expression2，否则返回Expression1。等价于：CASE WHEN Expression1 IS NULL THEN Expression2 ELSE Expression1 END。2 2、ISNULL函数，实际应用常用...
NULLIF is equivalent to a searched CASE expression in which the two expressions are equal and the resulting expression is NULL.We recommend that you not use time-dependent functions, such as RAND(), within a NULLIF function. This could cause the function to be evaluated twice and to return ...
NULLIF is equivalent to a searched CASE expression in which the two expressions are equal and the resulting expression is NULL. We recommend that you not use time-dependent functions, such as RAND(), within a NULLIF function. This could cause the function to be evaluated twice and to return...