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:

count
6

Code Explanation:

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:

Explanation :

Visual presentation:

Practice Online

Query Visualization:

Duration:

Rows:

Cost:

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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