SQL Exercises: Number of non NULL city values for salesmen
SQL Aggregate Functions: Exercise-19 with Solution
From the following table, write a SQL query to count the number of salespeople in a city. Return number of salespeople.
Sample table: salesman
Sample Solution :
SELECT COUNT(*) FROM salesman WHERE city IS NOT NULL;
Output of the Query:
The said SQL query to count the number of rows in the 'salesman' table where the "city" column is not NULL. The "COUNT(*)" function counts the number of rows in the table, and the "WHERE city IS NOT NULL" clause specifies that only rows where the "city" column is not NULL should be counted.
Relational Algebra Expression:
Relational Algebra Tree:
Note: The pictorial represetation above is based on hypothetical table for the purpose of explanation only. Your answer may not match.
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