Why Do ANSI-89 SQL Joins Persist Despite the Advantages of ANSI-92?

ANSI-89 SQL Joins: Why They Endure

Although ANSI-92 SQL joins are the modern standard, ANSI-89 joins remain surprisingly common. While the difference might seem negligible for simple queries, ANSI-92 provides significant advantages for complex scenarios.

Performance: The Myth Debunked

Contrary to common assumptions, research by Gulutzan and Pelzer found no measurable performance difference between ANSI-89 and ANSI-92 joins across various database systems. This suggests that database engines translate both syntaxes into an internal format before optimization, effectively neutralizing any inherent performance discrepancies.

ANSI-92's Strengths: Clarity and Efficiency

Despite the lack of performance gains, ANSI-92 offers superior readability and usability. The improved structure, combining join conditions with table specifications, simplifies identifying potential join problems. Centralizing filtering in the WHERE clause enhances query organization. Furthermore, ANSI-92's outer join syntax is more intuitive than Oracle's ( ) notation.

Inertia and Resistance to Change

Several factors impede the wider adoption of ANSI-92. Habitual reliance on copy-pasted code from older examples contributes to the continued use of ANSI-89. Additionally, some programmers find it challenging to adapt to new syntax, preferring rote memorization over conceptual understanding.

Nevertheless, a gradual transition towards ANSI-92 is underway. As programmers appreciate its readability and ease of use, its prevalence is expected to grow.

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