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SQL Program 48: Calculate running order total

Praveen KulkarniPraveen Kulkarni

SQL learning illustration

CS TECHIIE | SQL Notes and Solutions

Practical SQL exercise: Calculates a cumulative sum without collapsing rows.

Objective

Calculates a cumulative sum without collapsing rows.

Explanation

Read the statement clause by clause and predict the result before executing it. These examples use common relational SQL; table setup and exact syntax can vary between MySQL, PostgreSQL, SQL Server, Oracle and SQLite.

Safety check

Before running UPDATE or DELETE, run a SELECT with the same WHERE condition. Use a test database and a transaction for changes you need to verify.

Program / SQL Solution

SELECT order_id,order_date,amount,SUM(amount) OVER (ORDER BY order_date,order_id) AS running_total FROM orders;

Practice and revision

  • Run the example and verify the output.
  • Change the input and test normal, boundary and invalid cases.
  • Write the solution again without looking at the notes.

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