Re: LIKE pattern

On Mon, May 9, 2016 at 11:41 PM, SoDupuDupu wrote:
> Владимир-3 wrote
>> It seems my quite complex query runs 10 times faster on "some_column
>> LIKE '%test_1' " vs "some_column LIKE 'test_1' "
>> So I just add "%"  to the pattern...
>
> Keep in mind then LIKE '%test_1' and LIKE 'test_1' are not equivalent, using
> the % as a prefix to the argument means that the scan only has to confirm
> that the value ends in 'test_1' where forgoing the % entirely means that you
> are essentially saying some_column='test_1'.

Yes, but wouldn't the latter test be more efficient usually since it
tests against a prefix - at least with a regular index?

Kind regards

robert

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