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Archives: July 2011
SQLSkills Immersion training in London
Just short of the winter solstice, I bailed out of a freezing cold Johannesburg for warmer climates; well, actually for London where the weather could almost have been mistaken for a South African winter, except much wetter.
However I wasn’t going to London for the weather (fortunately), nor even for… Read more
2 comments, 504 reads
Posted in SQL In The Wild on 22 July 2011
Converting OR to Union
When I looked at indexing for queries containing predicates combined with OR, it became clear that the are some restrictive requirements for indexes for the optimiser to consider using the indexes for seek operations.
- Each predicate (or set of predicates) combined with an OR must have a separate index
0 comments, 629 reads
Posted in SQL In The Wild on 5 July 2011