Hint (SQL)

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In various SQL implementations, a hint is an addition to the SQL standard that instructs the database engine on how to execute the query. For example, a hint may tell the engine to use or not to use an index (even if the query optimizer would decide otherwise).

Contents

Implementation

Different database engines use different approaches in implementing hints.

See also

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References

  1. MySQL 5.5 Reference Manual: 12.2.9.3 Index Hint Syntax
  2. Mike Ault: Oracle SQL Hints Tuning
  3. "Postgres Plus Advanced Server Performance and Scalability Guide: Query Optimization Hints". Archived from the original on 2014-04-19. Retrieved 2013-06-24.
  4. "Postgres Plus Advanced Server Oracle Compatibility Developer's Guide: Optimizer Hints". Archived from the original on 2014-04-19. Retrieved 2013-06-24.
  5. MSSQL 2017 Documentation