Will Switching to ANSI JOINs Improve the Performance of My Non-ANSI JOIN Queries?

ANSI vs. Non-ANSI JOINs: A Performance Perspective

Inquiry:

Our system relies heavily on stored procedures employing non-ANSI JOIN syntax. Will switching to ANSI JOINs yield performance improvements?

Response:

No, there's generally no performance difference between ANSI and non-ANSI JOIN queries. ANSI-92 syntax enhances readability by separating join conditions from filtering conditions (the WHERE clause).

Why Choose ANSI JOINs?

Despite comparable performance, ANSI JOINs offer significant advantages:

• Enhanced Readability: The clear separation of join and filter logic improves code comprehension.
• Reduced Ambiguity: The older ' ' notation for outer joins can lead to unpredictable results or implementation variations, unlike the consistent behavior of ANSI-92.
• Industry Standard: ANSI-92 is the prevalent standard among developers and DBAs; most tools default to this syntax.
• Cross Join Avoidance: ANSI JOINs help prevent unintentional cross joins, a common pitfall of the older syntax.

While non-ANSI JOINs might offer a slightly simpler visual representation as Cartesian joins, ANSI JOINs are superior due to their clarity, consistency, and adherence to industry best practices. It's crucial to avoid natural joins within ANSI-92 due to the potential for unintended joins.

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