table of Contents
One, function introduction
select /*+ use_hash(ici,ifc) */
ici.user_code, ifc.file_name
from issue_ipo_cust_info ici
left join issue_ipo_file_content ifc
on ifc.id = ici.file_id;use_hash can strengthen the association between tables and increase the efficiency of the query in the query. The specific principle has not been understood yet.
Two, compare
Comparison of running time as shown in the figure:
