Pl sql if not null

Active 1 year, 5 months ago. Viewed 19k times. Vet, RXR. Cdubois6 Cdubois6 49 1 1 gold badge 1 1 silver badge 2 2 bronze badges. Add a comment. Active Oldest Votes. Gurwinder Singh Gurwinder Singh Gurwinder Singh Rahul Patil Rahul Patil 5 5 bronze badges. Good point. Check this link for more information — Rahul Patil. Not by design or scheme, and while mine may have ended up being similar to yours, I described the functions within my answer.

I don't see the need to down-vote similar answers. Notice that if x is null or y is null, then x AND y is always null. The most important thing to remember is that in almost every case if any part of your expression evaluates to NULL , the entire expression will evaluate to NULL.

In addition, pay close attention to how you construct conditional statements and expressions, when an expression might evaluate to NULL. But what if you want to treat two NULL s as being equal when you compare two values? Marcus in the comments below suggests creating an isEqual function that handles this for you. Here's the implementation of Marcus's isequal function for dates:.

It is also a statement , albeit a ''no-op" no operation -it only passes control to the next statement. Here are two examples. Null values can be a real pain. They can cause unexpected failures and exceptions in your algorithms. They can mess up queries, either returning rows you didn't want or excluding rows when you want them. So, the first thing to do is to decide very carefully where and when you want to allow nulls. If a column's value should never be null, then define it that way.

If you are writing a subprogram procedure or function and a parameter's value should never be null, you cannot add NOT NULL to the parameter definition. Instead, you will need to do one of the following:. Use a datatype for the parameter that cannot be null. See the examples below. Add code to your subprogram to check or assert that the actual argument value is not null. Then, you declare your own subtype and make that new datatype not-nullable.

Let's take a look:. Note that the exceptions raised above occur before the procedure is even executed, so the exception handler of the procedure cannot trap the exception you do not see "Error!

That may be just what you want. But if you cannot use a NOT NULL datatype for your parameter or you want to be able to trap the exception inside the subprogram, then you should write your own assertion code that runs right at the top of the subprogram.

Here's an example:. Better yet is to use a predefined and application-standard assertion package. That way, your code could look more like this:. Active Oldest Votes. Peter Lang Peter Lang Thanks for your answer. Is that the only way to check a if a record is null?

It's weird to me that we can assign null to a record, but can't check if a record is null. Good workaround! I use assignment of NULL to record and this is the way to make check! Instead why not just raise an exception when there's no data there: I realise that the others in the exception is highly naughty but it'll only really catch my table disappearing when it shouldn't and nothing else.

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