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SQL Query: 3 Methods for Calculating Cumulative SUM

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SQL provides various constructs for calculating cumulative sums, offering flexibility and efficiency in data analysis. In this article, we explore three distinct SQL queries that facilitate the computation of cumulative sums. Each query leverages different SQL constructs to achieve the desired outcome, catering to diverse analytical needs and preferences. Using Window Functions (e.g., PostgreSQL, SQL Server, Oracle) SELECT id, value, SUM(value) OVER (ORDER BY id) AS cumulative_sum  FROM your_table; This query uses the SUM() window function with the OVER clause to calculate the cumulative sum of the value column ordered by the id column. Using Subqueries (e.g., MySQL, SQLite): SELECT t1.id, t1.value, SUM(t2.value) AS cumulative_sum FROM your_table t1 JOIN your_table t2 ON t1.id >= t2.id GROUP BY t1.id, t1.value ORDER BY t1.id; This query uses a self-join to calculate the cumulative sum. It joins the table with itself, matching rows where the id in the first table is greater than or

How to Delete an Item from a Set in Python: Best Example

Set is a built-in data type in Python. Furthermore, it is an unordered collection without duplicate items. Here are the two methods that explain to delete an item from a Set.

Methods to delete an item from a Set

  • discard
  • remove



Discrd Vs. Remove


  • discard() will not raise an error if the item to remove does not exist.
  • The remove() will raise an error if the item does not exist.


Remove items from Set


Explanation to discard and remove methods


Python program:

#Prints all the Set items

food = {"pasta", "burger", "hot dog", "pizza"}

print(food)


# Prints the Set items without pasta

food.discard("pasta")

print(food)


# Prints the Set items without burger and pasta

food.remove("burger")

print(food)


# The next two lines try to remove an item that isn't in the set!

food.discard("pasta")  # this will not report an error

food.remove("pasta")   # this will report an error


The output:

{'pasta', 'burger', 'pizza', 'hot dog'}

{'burger', 'pizza', 'hot dog'}

{'pizza', 'hot dog'}

Traceback (most recent call last):

  File "main.py", line 12, in <module>

    food.remove("pasta")   # this will report an error

KeyError: 'pasta'


** Process exited - Return Code: 1 **

Press Enter to exit terminal


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