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 which version the optimization was added in. See the legend below the diagram to tell which color means which version.
Links to pages about individual optimizations:
- Non-semi-join Materialization (including NULL-aware and partial matching)
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