1、java8 Map的新用法 Job job = new Job("李四","语文",98); Job job1 = new Job("李四","数学",85); Job job2 = new Job("王五","语文",90); Job job3 = new Job("王五","数学",84); Read More
1、回访问题上、下排序sql语句 UPDATE table_bank bank join table_bank visit on (bank.id = 1 and visit.id = 23) or (bank.id=23 and visit.id =1) SET bank.order_no = v Read More
索引与优化like查询 1. like %keyword 索引失效,使用全表扫描。但可以通过翻转函数+like前模糊查询+建立翻转函数索引=走翻转函数索引,不走全表扫描。 2. like keyword% 索引有效。 3. like %keyword% 索引失效,也无法使用反向索引。 1. 使用下面 Read More