摘要:
问题:有一张表hy_test,查找其字段name中包含ufo的记录数,下面哪种方案最快? A.select count(*) from hy_test where name like '%ufo%' B.select count(*) from hy_test where instr(name,'u 阅读全文
摘要:
select /*+ leading(s@a) use_nl(s@a,s */ stuid,courseid,score from score s where s.stuid in (select /*+ qb_name(a) */ stuid from student where stuname 阅读全文