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.

Dec 23, 2024 · In SQL, some records in a table may not have values for every field, and such fields are termed as NULL values. These occur when data is unavailable during entry or when the attribute does not apply to a specific record.

Oct 24, 2024 · In SQL, NULL represents a missing or undefined value in a database. It is used to denote the fact that the value in a field is absent or unknown. A common beginner problem with NULLs is that your database will often not show NULLs explicitly.

May 18, 2011 · On MS SQL Server, the ISNULL () function returns the first argument if it's not NULL, otherwise it returns the second. You can effectively use this to make sure a query always yields a value instead of NULL, e.g.: Other DBMSes have similar functionality available.

Nov 9, 2021 · How to Insert Rows with NULL Values in SQL? In SQL, due to lack of data, we sometimes need to insert rows with NULL values in the tables. Here, the keyword NULL (without quotes) is used to represent no data. There are some key points of Null value: NULL value is different from a zero value.

Jun 20, 2024 · NULL is completely separate and follows different rules than non-null values. The ISNULL function will be used throughout this tip. It seemed best to introduce it at the top. It accepts two parameters: a value and a replacement.

Apr 26, 2023 · Any attempt to use NULL in an arithmetic equation will result in NULL. For example, 1 + NULL = NULL, 1 – NULL = NULL, 1 * NULL = NULL, and 1 / NULL = NULL. If we query the SpecialOfferID, Description, MinQty, and MaxQty fields in the Sales.SpecialOffer table, we’ll see some values in the MaxQty column are NULL.

Feb 24, 2025 · What is Null in SQL? In SQL, NULL represents missing or unknown data and is not the same as zero or an empty string. It signifies the absence of a value in a database column. Since NULL is not a concrete value, it behaves differently in queries and calculations.

Jan 16, 2025 · NULL values in databases often create confusion for both beginners and experienced DBAs. While it simply indicates a "lack of value," its behavior can cause unexpected results in queries and...

Mar 3, 2025 · Learn effective strategies how to handle NULL values in SQL queries to ensure accurate data retrieval and maintain database integrity.