FORCE_ORDER (JOIN Option)
FORCE_ORDER causes the query optimizer to honor the order of the joins specified in the SQL statement, rather than reordering the join. If FORCE_ORDER is not specified, the optimizer might switch the order of joins to improve the query execution plan.
This is currently used to prevent:
• Union join flipping
• Join reordering
• Reordering of join while selecting the join algorithm, even if a cardinality estimate is provided.
For information on SQL join reordering, see the TDV User Guide.
Operator
JOIN
Syntax
force_order
Example
SELECT column1 FROM table1 INNER {OPTION force_order}
JOIN table2 ON table1.id = table2.id