QuerydrillHeadcount per department
An SQL exercise from Querydrill. Solve it with a SQL editor in your browser, checked on the rows it returns and again on changed data, and it is checked the moment you submit.
The task
Return every department name and its number of employees. Departments with no employees must show 0.
What this exercise teaches
COUNT(*) would count the empty match as 1. COUNT(e.id) skips NULLs and gives 0.
A hint if you get stuck
LEFT JOIN from departments, and count a column from employees, not *.
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