Semijoin Option Syntax Examples
Query option hints can be written into the SQL of the query to suggest that the TDV query engine use a semijoin in the query. For example:
SELECT column1 FROM table1 INNER {OPTION SEMIJOIN} JOIN table2 ON table1.id = table2.id
A query hint, enclosed in curly braces immediately precedes the JOIN keyword.
The default value of OPTION SEMIJOIN is True, so the value of semijoin does not have to be explicitly set. You can also specify something more specific like:
… INNER {OPTION SEMIJOIN, PARTITION_SIZE=20} JOIN …
This option forces the semijoin to be partitioned, with each partition having no more than 20 elements.