when i modify a query
select a,b,c from test1,test2 where (condition)
select index(indexname) a,b,c from test1,test2 where (condition).
the query plan changes. before analyzing the query plan change. i need to unnderstand when the syntax for the hint is not correct, how does the query is influenced by the hint.
correct syntac should be index( tablename indexname).
i know i have not given much info, but i want to know index(indexname) hint, what does it do ?