Nul Value .: (!)

Nul Value

(a) A value of NUL indicates that the value is unknown.

FORMULATED example: delusional- is the knowledge or feeling something is there, when in fact the individual realizes there is a cause to notice it.

(b) A value of NUL is different from an empty or zero value.-

(c) No two nul values are equal.

(d)Comparisons between two null values,
or between a NUL and any other value,
return unknown because the value of each NUL is unknown.

FORMULATED- example: fuel dependency of projectiles – water, land, air, space, must break the nul value to achieve operation and passage
within my formula the nul value passes though nul value barriers without causing environmental disruption and damage and can be identified
for example the air we breath, the earth we live on and all areas we go to or travel through including space.

Founder & Director A-Z Tek Operations Inc.
Mr. Glenn Allan Garner


from file




wikipedia – Search Null (SQL)

wikipedia – Search Index

wikipedia – Search Nul Values search=NUL+VALUE&title=Special%3ASearch&go=Go

wikipedia – Search Triangular numbers


The Oracle NVL function accepts two parameters. It returns the first non-NULL parameter or NULL if all parameters are NULL.

A COALESCE expression can be converted into an equivalent NVL expression thus:

COALESCE ( val1, ... , val{n} )

turns into:

NVL( val1 , NVL( val2 , NVL( val3 ,  , NVL ( val{n-1} , val{n} )  )))

A use case of this function is to replace in an expression a NULL value by a fixed value like in NVL(SALARY, 0) which says, ‘if SALARY contains a NULL value, replace it with 0′.

There is, however, one notable exception. In most implementations, COALESCE evaluates its parameters until it reaches the first non-NULL one, while NVL evaluates all of its parameters. This is important for several reasons. A parameter after the first non-NULL parameter could be a function, which could either be computationally expensive, invalid, or could create unexpected side effects.

Data typing of Null and Unknown[edit]

See also: Option type and Nullable type

The NULL literal is untyped in SQL, meaning that it is not designated as an integer, character, or any other specific data type.[24] Because of this, it is sometimes mandatory (or desirable) to explicitly convert Nulls to a specific data type. For instance, if overloaded functions are supported by the RDBMS, SQL might not be able to automatically resolve to the correct function without knowing the data types of all parameters, including those for which Null is passed.

Conversion from the NULL literal to a Null of a specific type is possible using the CAST introduced in SQL-92. For example: