Use this where standard SQL would be used and where you can easily combine it with other conditions in an SQL WHERE clause.
可以将它用在能够使用标准 SQL 的地方,而且可以将它与 SQL WHERE 中的其他条件轻松地组合在一起。
In the meantime, you also should try to add extra predicates into your WHERE clause to match other WHERE clauses.
与此同时,还可以尝试向WHERE子句中添加额外的谓语来匹配其他WHERE子句。
For comparison, Figure 3 illustrates the access plan where I forced the DB2 optimizer to ignore the index by adding the clause SELECTIVITY 1 to the predicate in the where clause.
为了便于比较,图3显示了通过将SELECTIVITY 1子句添加到where子句的谓词中,强迫db2优化器忽略索引的访问计划。
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