1 row in set (0.00 sec) 可以看到,type变为了ref,Extra中的Using filesort也消失了,结果非常理想。 再来看一个多表查询的例子。 首先定义3个表class和room。 复制代码代码如下: CREATE TABLE IF NOT EXISTS `class` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `card` int(10) unsigned NOT NUL...
He explained who each person in the photo was. 他对照片里的人一一作了介绍。 牛津词典 Not every judge, however, has the ability to explain the law in simple terms... 然而,不是每个法官都能用简单的语言来解释法律。 柯林斯高阶英语词典 Don't sign anything until your solicitor has explained ...
物化子查询尽可能使用内存中存储临时表,若表太大,会退回到磁盘上存储(可参考8.4.4 Internal Temporary Table Use in MySQL)。 2.4.2 与不使用物化的比较 物化子查询使用临时表避免了优化器的某些重写,并使得子查询尽可能只执行一次,而不是对外部查询的每一行执行一次。 如果未使用物化,则优化器有时会将不相关的...
3. At the class meeting, Wang Fang A her learning plan to us in detail. A. explained B. discussed C. created 相关知识点: 试题来源: 解析 答案见上3A 【解析】句意:在班会上,王芳向我们详细说明了她的 学习计划。explain解释,说明;discuss讨论; create创造。故选A。
A. speak loudly B. speak slowly C. make it easy to understand D. make it difficult to understand 相关知识点: 试题来源: 解析 C。“explain clearly”意思是解释清楚,也就是让问题容易理解。A 选项是大声说;B 选项是慢慢说;D 选项是让问题难以理解,都不符合“解释清楚”的意思。反馈...
where a in(…) order by b,c /*对于排序来说,in 相当于是范围查询*/ 慢查询 简介 开启慢查询日志,可以让MySQL记录下查询超过指定时间的语句,通过定位分析性能的瓶颈,才能更好的优化数据库系统的性能。 一、配置慢查询 1、参数说明 slow_query_log : 慢查询开启状态(默认关闭) ...
Classify the image to get the class label. Get scores = predict(net,single(X)); label = scores2label(scores,classes) label = categorical toy poodle Use gradCAM to determine which parts of the image are important to the classification result. Specify the softmax layer in the network as...
57. Where do you think most of the people live, in the central part of the country or ___the coast 58. We are not allowed___(talk) aloud in class. It is the same with the students in other classes. 59. His wonderful performance left a deep impression ___the audience. 60. With...
1 Can you explain ___ you don't listen to your English teacher in class?A. why it is thatB. why is it thatC. how it is thatD. how is it that 2 Can you explain ___ you don't listen to your English teacher in class?A. why it is thatB. why is it thatC. how it is...
C Vocabulary C1 The words in italics explain the meanings of some words on page 99. Find these words to complete the sentences. Change their forms if necessary.1 Last night, we saw a humorous TV programme and laughed a lot. (funny) (introduction)2 After you complete this task , report ...