SQL is the dominant technology for accessing application data. It is increasingly becoming a performance bottleneck when it comes to scalability. Given its dominance, SQL is a crucial skill for all engineers.
Subqueries are commonly used in database interactions, making it important for a programmer to be skilled at writing them.
Public questions (free account) are common interview questions. They are great for practicing, or if you want to filter candidates using the classic problems.
Given the following data definition, select all queries that return a list of employees who are not managers.
TABLE emp id INTEGER NOT NULL PRIMARY KEY mgrId INTEGER REFERENCES emp (id) name VARCHAR(30) NOT NULL