What Is Null Value Sql

A null value in a relational database is used when the value in a column is unknown or missing. A null is neither an empty string (for character or datetime data types) nor a zero value (for numeric data types).

Is SQL NULL or value?

NULL is used in SQL to indicate that a value doesn’t exist in the database. It’s not to be confused with an empty string or a zero value. While NULL indicates the absence of a value, the empty string and zero both represent actual values.

Is NULL 0 in SQL?

SQL’s coalesce turns a null value into another value. The example returns the result of the expression, unless it is null , then it returns zero ( 0 ). Coalesce takes an arbitrary number of arguments and returns the first not null value or null if all arguments are null .