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SQL Exercises: Count the number of different non-NULL city values for salespeople

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

Relational Algebra Expression:

Relational Algebra Expression: Count the number of different non NULL city values for salesmen.

Relational Algebra Tree:

Relational Algebra Tree: Count the number of different non NULL city values for salesmen.

Explanation :

Syntax of counts the number of different non NULL city values for salesmen

Pictorial presentation:

Result of counts the number of different non NULL city values for salesmen

Practice Online


Query Visualization:

Duration:

Query visualization of Count the number of different non NULL city values for salesmen - Duration

Rows:

Query visualization of Count the number of different non NULL city values for salesmen - Rows

Cost:

Query visualization of Count the number of different non NULL city values for salesmen - 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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Previous: From the following table, write a SQL query to count all the orders generated on '2012-08-17'. Return number of orders.
Next: From the following table, write a SQL query to count number of orders by the combination of each order date and salesperson. Return order date, salesperson id.

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SQL: Tips of the Day

SQL Server SELECT into existing table. 

INSERT INTO dbo.TABLETWO
SELECT col1, col2
  FROM dbo.TABLEONE
 WHERE col3 LIKE @search_key

This assumes there's only two columns in dbo.TABLETWO - you need to specify the columns otherwise:

INSERT INTO dbo.TABLETWO
  (col1, col2)
SELECT col1, col2
  FROM dbo.TABLEONE
 WHERE col3 LIKE @search_key

Database: SQL Server

Ref: https://bit.ly/3y6tpA3