上一讲详细叙述了explain结果中最重要的type字段（连接类型）的含义。explain结果中还有一个Extra字段，对分析与优化SQL有很大的帮助，今天继续和大家聊一聊explain。 通过构造各类SQL语句，对explain的Extra字段进行说明，启发式定位待优化低性能SQL语句。 Extra为Using ...

Since 2003, John Walsh has led WOLA’s efforts to promote more humane and effective drug policies, documenting the damage caused... The U.S. military attacks that began last September, targeting boats ...

Copyright 2026 The Associated Press. All Rights Reserved. Copyright 2026 The Associated Press. All Rights Reserved. A U.S. Capitol Police officer patrols on the East ...

The consumer price index rose 2.7% in December 2025 from 12 months earlier, unchanged from November, according to the Bureau of Labor Statistics. Tariffs put some upward pressure on prices for ...

Plenty of presidents have reached for a salty four-letter word when the moment felt right, but why would the Trump administration stop there? This week it’s been getting significant mileage from a ...

Crime rates in the U.S. fell in 2025. Murders in particular fell dramatically. That is a major takeaway among criminal justice experts as we approach the year's end. Crime rates in the U.S. fell ...

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The rate of homicides has plummeted nationwide and, in 2025, is trending toward its lowest level in decades. The steady decline has reversed the surge of slayings seen during the peak of the covid-19 ...

Liquidity in the economy has decreased due to factors like quantitative tightening and the increase of the debt ceiling. Bitcoin's price has previously shown a correlation to liquidity. Analysts at ...