[SQL] Index problem...

I want to query this... --> SELECT * FROM bbs ORDER BY ref desc, step ASC LIMIT 12; this query doesn't refer the index that made by this query. --> CREATE INDEX idx_bbs ON bbs (ref, step); but, i change the query that "ref desc" to "ref asc". then query refer the index, and i can see a result

[SQL] How to make operator class?

when create indexes, use operator class like this. CREATE INDEX idx_name ON tbl_name (col_name [operator class]); so, i made an operator. but i think that it is different operator class because operator class doesn't work at all. then, how to make operator class?

[SQL] Index Problem

I want to query this... --> SELECT * FROM bbs ORDER BY ref desc, step ASC LIMIT 12; this query doesn't refer the index that made by this query. --> CREATE INDEX idx_bbs ON bbs (ref, step); but, i change the query that "ref desc" to "ref asc". then query refer the index, and i can see a result v

[SQL] Index Problem

I want to query this... --> SELECT * FROM bbs ORDER BY ref desc, step ASC LIMIT 12; this query doesn't refer the index that made by this query. --> CREATE INDEX idx_bbs ON bbs (ref, step); but, i change the query that "ref desc" to "ref asc". then query refer the index, and i can see a result