For all of the vast improvements that 4D v11 SQL provides over its predecessors with respect to performance and scalability, some of the more subtle aspects of this latest offering are worth spending some time with. Case in point is 4Dís support of NULL values. A NULL value is a value that exists, but its contents are unknown. This tech note covers the uses for NULL values, the language commands in 4D and SQL that developers can use to manipulate them and their behavior in 4D v11 SQL.

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