While experimenting with several different ways of structuring the query referenced in "Improving Query Performance", I mentally raised a question I hope someone can answer.
The following two queries appear to be functionally equivalent...that is to say the results they produce are identical. Is there any intrinsic advantage to one over the other? If so, what is that advantage? select distinct RESPONSES.RESPONSE_OID from RESPONSES, DATA_ELEMENTS, SEQUENCE_ELEMENTS where RESPONSES.definition_parent = DATA_ELEMENTS.DATA_ELEMENT_OID and RESPONSES.instance_parent = SEQUENCE_ELEMENTS.SEQUENCE_ELEMENT_OID and SEQUENCE_ELEMENTS.SEQUENCE_ELEMENT_NAME = :sequence_element_name and DATA_ELEMENTS.DATA_ELEMENT_NAME = :data_element_name select distinct RESPONSES.RESPONSE_OID from RESPONSES join SEQUENCE_ELEMENTS on (SEQUENCE_ELEMENTS.SEQUENCE_ELEMENT_OID = RESPONSES.instance_parent) join DATA_ELEMENTS on (DATA_ELEMENTS.DATA_ELEMENT_OID = RESPONSES.definition_parent) where SEQUENCE_ELEMENTS.SEQUENCE_ELEMENT_NAME = :sequence_element_name and DATA_ELEMENTS.DATA_ELEMENT_NAME = :data_element_name _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
