5.7 Grouping methods
There are two types of grouping methods:
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Hash grouping
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Sort grouping
Grouping is performed when the GROUP BY clause or the DISTINCT set function is specified. This section explains the grouping methods.
HADB automatically determines which grouping method to use. You can find out which grouping method was used by viewing the access path after the SQL statement is executed. For details about access paths, see the following subsections:
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How to check access paths
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Information that is displayed as access paths
See (13) Grouping methods in 6.1.4 Information displayed in the tree view.
- Note
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You can prevent the application of global hash grouping by specifying a grouping method specification. For details about grouping method specifications, see Specification format and rules for GROUP BY clauses in the manual HADB SQL Reference.
- Organization of this section