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What is a NULL Value? A field with a NULL value is a field with no value. If a field in a table is optional, it is possible to insert a new record or update a record without adding a value to this field. Then, the field will be saved with a NULL value.
17 mar 2021 · Simply put, an SQL NULL means that we don’t have a value for that particular field. Maybe we don’t know what the value will be and we need a placeholder, like when an order has been shipped to a customer but not delivered yet; in that case, the delivery date will be NULL until the order has arrived.
A null indicates a lack of a value, which is not the same thing as a zero value. For example, consider the question "How many books does Adam own?" The answer may be "zero" (we know that he owns none) or "null" (we do not know how many he owns).
20 cze 2024 · This tip will help you understand what NULL means in the context of the Microsoft Fabric data universe, which includes SQL Server. It will then show how these values can make queries act unexpectedly and how to best interact with NULL values to avoid problems.
NULL in SQL represents missing or unknown values. It is not zero, not an empty string, or not any other default value. It’s simply a representation of ‘no data’. It’s important to understand that a NULL value isn’t equivalent to anything else, not even another NULL value.
What is NULL. NULL is special in SQL. NULL indicates that the data is unknown, inapplicable, or even does not exist. In other words, NULL represents the missing data in the database. For example, if employees do not have phone numbers, you can store their phone numbers as empty strings.
10 cze 2023 · NULL values represent an unknown value and are often found in SQL statements and table columns. They behave differently to other values and you need to be aware of some differences, especially when working with NOT IN and NOT EXISTS.
