| 摘要 |
A method and apparatus for optimizing a query for a relational database are disclosed. The techniques employed enable a group-by operator to be an internal node. In particular, the optimization techniques include the steps of receiving a query having group-by to be optimized, generating for the query execution plans where placing group-by preceding every internal join node are considered, estimating cost for the execution plans, and choosing the execution plan having the lowest estimated cost.
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