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SQL programmingYou can use the HCL OneDB™ implementation of the SQL language to develop applications for HCL OneDB™ database servers.
Guide to SQL: SyntaxThe HCL OneDB™ Guide to SQL: Syntax describes the syntax of the statements, data types, expressions, operators, and built-in functions of the HCL OneDB™ dialect of the SQL language.
SQL statementsThis chapter describes the syntax and semantics of SQL statements that are recognized by HCL OneDB™.
CREATE AGGREGATE statementUse the CREATE AGGREGATE statement to create a new aggregate function and register it in the sysaggregates system catalog table.
Parallel ExecutionThe database server can break up an aggregate computation into several pieces and compute them in parallel.

Parallel Execution

The database server can break up an aggregate computation into several pieces and compute them in parallel.

The database server uses the INIT and ITER support functions to compute each piece sequentially. Then the database server uses the COMBINE function to combine the partial results from all the pieces into a single result value. Whether an aggregate is parallel is an optimization decision that is transparent to the user.