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SQL Optimizer for DB2 ZOS 5.5.1 - User Guide

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STARJOIN

Use to perform a star join.

Star join allows you to join a dimension column of a fact table to the key column in the corresponding dimension table.

 

TBSCAN

Use to read every row in a table.

A table space scan construct consists of two nodes: a TBSCAN node and some type of table node such as a base table, a materialized query table, a work file, a pipe, or a table function.

 

TRUNCATE

Denotes TRUNCATE statement.

A TRUNCATE statement deletes all rows for either declared global temporary tables or base tables.

 

UNION

Combine rows from multiple tables and remove duplicate rows.

A UNION construct contains a UNION node and at least one subtree. Each subtree contains a WFSCAN node, a WORKFILE node, a SORT node, and the source query block node.

 

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