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SQL Anywhere 12.0.0 (Français) » SQL Anywhere Server - SQL Usage » Query optimization and execution » Semantic query transformations


Optimization of LIKE predicates

LIKE predicates involving patterns that are either literal constants or host variables are very common. Depending on the pattern, the optimizer may rewrite the LIKE predicate entirely, or augment it with additional conditions that could be exploited to perform indexed retrieval on the corresponding table. Additional conditions for LIKE predicates utilize the LIKE_PREFIX predicate, which cannot be specified directly in a query but appear in long and graphical plans when the query optimizer can apply the optimization.