null vs not null

SQL NOT NULL Constraint. By default, a column can hold NULL values. The NOT...

SQL NOT NULL Constraint. By default, a column can hold NULL values. The NOT NULL constraint enforces a column to NOT accept NULL values. This enforces.

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When I insert a blank record into a NULL row it inserts NULL while insertin...

When I insert a blank record into a NULL row it inserts NULL while inserting into NOT NULL it seems to insert a space: " ". if you insert a blank into a field defined NOT NULL, you get a blank. NULL . versus the following.

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Deciding if a column should be NULL or NOT NULL will be an important piece ...

Deciding if a column should be NULL or NOT NULL will be an important piece of this work, and sometimes far more contentious than we'd.

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The useful NULL condition lets you represent unknown values in a The Common...

The useful NULL condition lets you represent unknown values in a The Common Language Runtime (CLR) in Visual Studio (VS)

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It is important to know the difference between NULL, NOT NULL and Zero/Whit...

It is important to know the difference between NULL, NOT NULL and Zero/White Spaces in Database. Imagine you have a screen to fill user.

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In this case, we set dwn.220.v.uaors_id to NOT NULL to prevent it from ever...

In this case, we set dwn.220.v.uaors_id to NOT NULL to prevent it from ever holding a NULL value. This suits the example we've been looking at because films in.

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In a MySQL table, you can obviously set an INT as both NOT NULL and AUTO_IN...

In a MySQL table, you can obviously set an INT as both NOT NULL and AUTO_INCREMENT, but while they both work together, is the former.

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The simple action of translating the "NOT(MyColumn IS NULL)" into...

The simple action of translating the "NOT(MyColumn IS NULL)" into "MyColumn IS NOT NULL" isn't it an inefficiency, though small?

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to determine the difference between a NOT NULL constraint, created like: th...

to determine the difference between a NOT NULL constraint, created like: this is a column level check vs a table level check), select out the search condition.

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You have to distinguish two situations: you compare one COLUMN against NULL...

You have to distinguish two situations: you compare one COLUMN against NULL, or you compare the whole ROW (RECORD) against NULL.

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Different types of languages deal with this "value" in diverse wa...

Different types of languages deal with this "value" in diverse ways. You can have a more comprehensive list of what NULL can mean on this.

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In MySQL, when you define a column as NOT NULL, it doesn't mean "...

In MySQL, when you define a column as NOT NULL, it doesn't mean "this column must have a value." It doesn't mean "this column can't be.

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A comparison of three methods to fetch rows present in one table but absent...

A comparison of three methods to fetch rows present in one table but absent in another one, namely NOT IN, NOT EXISTS and LEFT JOIN / IS.

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When writing DDL in SQL, you can specify a couple of constraints on columns...

When writing DDL in SQL, you can specify a couple of constraints on columns, like NOT NULL or DEFAULT constraints. Some people might.

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There are lots of ways to learn new things, or be reminded of old things. O...

There are lots of ways to learn new things, or be reminded of old things. One of my favorites is the QotD on sql server central. Recently there.

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