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Search Results for: subselect faster

When the subselect runs faster

A few weeks ago, we had a query optimization request from one of our customer. The query was very simple like:

This column in the table is looks like this:

The table have …

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Speed up GROUP BY queries with subselects in MySQL

We usually try to avoid subselects because sometimes they force the use of a temporary table and limits the use of indexes. But, when is good to use a subselect? This example was tested over …

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MySQL and PostgreSQL SpecJAppServer benchmark results

Listening to Josh Berkus presentation on OSCON today I decided to take a closer look at SpecJAppServer benchmarks results which were published by PostgreSQL recently and which as Josh Puts it “This publication shows that …

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Derived Tables and Views Performance

Starting MySQL 4.1, MySQL had support for what is called derived tables, inline views or basically subselects in the from clause. In MySQL 5.0 support for views was added. These features are quite related to …

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Database problems in MySQL/PHP Applications

Article about database design problems is being discussed by Kristian. Both article itself and responce cause mixed feellings so I decided it is worth commenting: 1. Using mysql_* functions directly This is probably bad but …

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MySQL Query Cache

MySQL has a great feature called “Query Cache” which is quite helpful for MySQL Performance optimization tasks but there are number of things you need to know. First let me clarify what MySQL Query Cache …

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