Lowe's Home Improvement Data Engineer interview questions

Describe a left join in sql

1) In which scenario Dataframe vs Dataset is needed 2)msck repair vs drop partition 3)How do you choose the number of mappers in sqoop? 4)Hive regex , merge queries 5)Spark application lifecycle 6)Spark read and parse JSON 7)Cache vs Persist 8)Parquet vs Avro 9)Spark production code deployment process 10)Spark map , filter