GM DA 一轮电话面试

这周楼主收到recuiter的领英消息说General Motors有个职位和我很match,马上安排了今天的面试，GM hiring manager和senior project manager 面试我，这个职位的要求挺高，虽然title是DA，但干的活偏DS和DE,我面试前心里还挺虚的，结果两个面试官问的问题并不难，我都回答上了，希望下周通知二轮面试。
以下是面试问题：
sql:
How do you rating your sql skills?
what's difference between delete and truncate?
what's the difference between left join and right join?
what's the difference between dense_rank and rank?

ML
what's the difference between supervised learning and unsupervised leanring?
How are you using linear regression model?
What's the process when you work on machine learning project?
How large is your data set?
Statisticswhat is 95% confidence interval Z-score?

Power BI
How do you gather data source?
What's the process for dashboard development?

Performance tuning
If a query running slow, how do you trouble shoot it?