String.IsNullOrEmpty 类似 SQL 中 VARCHAR 的函数?

问题描述

假设我有一个接受多个 VARCHAR 参数的函数或存储过程.我已经厌倦了像这样编写 SQL 来测试这些参数是否有值:

Say I've got a function or stored procedure that takes in several VARCHAR parameters. I've gotten tired of writing SQL like this to test if these parameters have a value:

IF @SomeVarcharParm IS NOT NULL AND LEN(@SomeVarcharParm) > 0
BEGIN
    -- do stuff
END

必须有更好的方法来做到这一点.没有吗?

There's gotta be a better way to do this. Isn't there?

推荐答案

你可以做 ISNULL(@SomeVarcharParam, '') <>'' 或者您可以创建一个返回位的 UDF:

You can do ISNULL(@SomeVarcharParam, '') <> '' or you can create a UDF that returns a bit:

create function dbo.IsNullOrEmpty(@x varchar(max)) returns bit as
BEGIN
IF @SomeVarcharParm IS NOT NULL AND LEN(@SomeVarcharParm) > 0
    RETURN 0
ELSE
    RETURN 1
END

并使用 IF NOT dbo.IsNullOrEmpty(@SomeVarcharParam) BEGIN ...

请记住，在调用 UDF 时，您必须为其所有者添加前缀(此处为 dbo.)

Keep in mind that when calling a UDF, you MUST prefix the owner of it (here, dbo.)