4. 示例分析 示例1:全表扫描 EXPLAIN SELECT * FROM users WHERE name = 'John'; 输出: idselect_typetabletypepossible_keyskeyrowsExtra 1 SIMPLE users ALL NULL NULL 1000 Using where 问题: type 为ALL,表示全表扫描。 possible_keys 和key 为空,说明没有索引。
Stephen Colbert chats with John Dickerson about what to expect from Donald Trump's second term in The White House and how to talk to young people about it. #Colbert #JohnDickerson #CBSNews #Election2024 #StephenColbert #TheLateShow
也就是它负责保证SQL执行的效率最高,比如优化器决定Oracle 以什么样的方式来访问数据,是全表扫描(Full Table Scan),索引范围扫描(Index Range Scan)还是全索引快速扫描(INDEX Fast Full Scan:INDEX_FFS);对于表关联查询,它负责确定表之间以一种什么方式来关联,比如HASH_JOHN还是NESTED LOOPS 或者MERGE JOIN。
291, No. 4, October 2004, pp. 76–81. Books The Internet of Things: From Data to Insight by John Davies and Carolina Fortuna (eds). John Wiley & Sons, 2020. The Internet of Things by Samuel Greengard. MIT Press, 2015. A short, basic primer that covers the basic concepts, before ...
题目JOHN SNOW DEFEATS "KING CHOLERA" Cholera used to be one of the most(1)___(fear)disease in the world.In the early 19th century,when an outbreak of cholera hit Europe,millions of people died from the disease.John Snow became frustrated (2)___no one knew how ...
更多“You are John Smith who wants to purchase some office equipment (办公用品) . Write a letter of inquiry. T…”相关的问题 第1题 听力原文:M: Good morning. This is John Parker speaking. I'm just ringing to confirm my app ointment with Mr. Smith for this afternoon. W: Yes. Mr....
其实,他们所谓的“超级智能”早就被数学家和密码学家古德(Irving John Good)在20世纪60年代想过了,只不过那时“超级智能”被古德称为“智能爆炸”或Ultra-intelligence,或“超人智能”。古德是图灵在布莱彻利庄园和后来曼彻斯特大学时的小伙伴。他1967年7月7日从英国搬到美国,他戏言他是“第七个年代,第七年,第七...
LYELL, Charles (1797-1875). Principles of Geology, being an Attempt to Explain the Former Changes of the Earth's Surface, by Reference to Causes Now in Operation, London: John Murray, 1830-1833. 3 volumes, 8° (224 x 144mm). Half titles in volumes I & I
[2]. Wei Yang, Yan Tian, Mingmao Yang, John Mauck, Juan J. Loor, Bin Jia, Shuang Wang, Wenwen Fan, Zhendong Li, Bingbing Zhang, Chuang Xu. β-sitosterol Alleviates High Fatty Acid-Induced Lipid Accumulation in Calf Hepatocytes by Regulating Cholesterol Metabolism. JOURNAL OF STEROID BIOCHE...