If you find this article useful, please follow me. I write articles about skills you use in your daily work. 102.1 — I want my table back To retrieve a table at a timestamp, use SYSTEM_TIME: To restore a table:

I post articles that are related to daily work and not commonly shown in textbooks. Please follow me or throw me a thumb if you find this article useful. If you are looking for quick tips to tune the SQL performance, please check my first article: SQL Performance Tuning. Effectiveness: …

SQL Textbooks teach us how to get the results by writing queries. In the production environment, query execution time matters just as much since it influences user experience or even leads to a production incident of “Runtime Out” due to platform threshold setup. …

As a data science enthusiast, A/B Testing has always been in my interview questions. In this job-hunting process, I interviewed with TikTok (Product Marketing Analyst), Whole Food (Digital Marketing Campaign Result Analyst), and Sega of America (Data Analyst). …

— — Stored Function, Stored Procedure, Trigger, CTE, and Recursive CTE. Except for the basic SELECT-FROM-WHERE and common INSERT, UPDATE and DELETE, there are some other useful SQL queries including Stored Functions, Stored Procedures, Triggers, Common Table Expressions(CTE), and Recursive CTE. I will use MySQL for the classicmodels, which you…

What is AutoML and Why AutoML? AutoML automates methods for model selection, hyperparameter tuning, and model ensemble. It does not help feature engineering. AutoML works best for common cases including tabular data(66% of data used at work are tabular), time series, and text data. It does not work as good in deep learning because deep learning…

In 2014, an article “Do We Need Hundreds of Classifiers to Solve Real World Classification Problems?” shows the practical results from179 classifiers’ performance on 121 datasets. The answer is: there is no best classifier, but there is a most proper one for that dataset. Overall, Random Forest shows the best…

Optimization 1. Approximate Greedy Algorithm XGboost will always choose the best gain to determine the split point. So it is a greedy algorithm, which does not guarantee the best results for the long run. When there are a lot of features, it will run forever. So to deal with this, we…

The XGBoost is highly correlated with Gradient Boost. It stands for Extreme Grident Boost.