Subquery optimizations map
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Below is a map of subqueries.
- The map shows all kinds of subqueries allowed in SQL language. It shows
- Subqueries that have form
x IN (SELECT ...)
- Subqueries that are in the
FROM
clause - .. and so forth
- Subqueries that have form
- The size of the areas roughly corresponds to how important (i.e. frequently used) a particular kind of subquery is. For example,
x IN (SELECT ...)
are the most important. - Colored areas represent optimizations/execution strategies that are applied for particular kinds of subqueries.
- The color of the area shows where optimization was introduced: MySQL 5.1, MariaDB 5.3, or MySQL 5.6
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