Category: ASE

NULL, NULL Values

A NULL value is a not defined or unknown value. It is important to notice that NULL values in columns defined by exact numeric datatypes or decimal datatypes are not equal to "0". In columns defined by character datatypes the NULL value is not equal to a blank character. In both cases, NULL symbolises a non-existent value!

NULL values are ignored in queries using logical operators! Moreover, it can not be expected that two NULL values can be compared to each other.

ASE ® equally recognises the keyword NULL written in lower case and upper case. The Sybase defined default writing for NULL is in upper case letters.