null function in sql

1 Introduction to null valuesNULL is a unique data type in the database. If a column in a record is NULL, the value of this column is unknown and uncertain. Since it is unknown, there are several possibilities. Therefore, NULL is not a definite

The introduction of 1null value NULL is a unique data type in the database. When a column in a record is NULL, the value of this column is unknown and uncertain. Since it is unknown, there are several possibilities. Therefore, NULL is not a definite

In the database, a null value is used to indicate that the actual value is unknown or meaningless. In a table, if a column in a row has no value, it is called NULL ). A null value can be returned for any data type column as long as the non-NULL or

For more information about bugs fixed in SQL Server 2000 Service Pack 4, click the following article number to view the article in the Microsoft Knowledge Base:314128 FIX: When an RPC call is performed, Access with conflicting values includes an

Oracle in the database, null values are used to indicate a situation where the actual value is unknown or meaningless. In a table, if a column in a row has no value, it is called a null value (NULL). Columns of any data type can have null values if

Correct use and space occupation of NULL in SQL Server, servernull We often encounter NULL in the use or maintenance of SQL Server. What is NULL? The following is a brief description provided by MSDN (see "Null Values "): A value of NULL

(ii) SQL statement fuzzy query NULL processing aggregate functionMy own study notes, reproduced please indicate the source, thank you!---sauerkrautSQL: Structured Query Language (structured Query Language), a standard language for relational

NULL in the computer and programming world represents an unknown, indeterminate. Although the Chinese translation is "empty", this empty (null) is not Pethin (empty). Null represents an unknown state, the future state, such as how much money in Xiao

NULL in the computer and programming world represents an unknown, indeterminate. Although the Chinese translation is empty, this empty (null) is not Pethin (empty). Null represents an unknown state. In the future, I don't know how much money I have

Although the person who is proficient in SQL will not have any questions about NULL, but the whole article is still very difficult to find, see an English version, feel good.Tony Hoare invented the null reference in 1965 and considered it a