Oracle Joins: Conventional ( ) vs. ANSI JOIN – Which Syntax Should You Use?

Oracle Joins: Conventional vs ANSI Syntax

Q: Is there a significant difference between using conventional joins with the " " operator and ANSI syntax with the "JOIN" keyword?

A: The primary distinction is clarity and consistency. ANSI syntax is part of the SQL standard and is preferred because it reduces the chances of errors. If a ( ) is omitted in a multi-column outer join when using conventional joins, the result will be an inner join. ANSI syntax resolves this issue by explicitly defining the join type (LEFT, RIGHT).

Q: Are there any performance or limitation considerations when using either syntax?

A: Performance-wise, there is no discernible difference between the two syntaxes. However, there are a few potential limitations:

• In older versions of Oracle (<11.2), there were reported bugs with ANSI syntax, which have been resolved in newer versions.
• Using conventional joins with the " " operator in non-optimized Oracle versions may lead to more efficient database operations.

Q: Do you have any recommendations for making the transition to ANSI syntax?

A: If your existing 200 packages are functioning properly using conventional syntax, it's generally advisable to leave them as-is. Modifying them to use ANSI syntax will not result in a performance improvement. However, if you plan to migrate to another RDBMS product or value the clarity and consistency of ANSI syntax, it may be beneficial to consider the change.

Q: Are there any freeware tools available for rewriting conventional joins to ANSI syntax?

A: Unfortunately, we do not have any specific recommendations for freeware tools that can perform this task.

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