How to use Aggregate Functions with Conditional Expressions In MariaDB

How to Convert Rows into Columns?

Sometimes when dealing with databases there are some situations where data stored in rows needs to be pivoted or converted into columns for better analysis or reporting. Below are the approaches that help us to convert rows to columns in MariaDB are as follows:...

1. Using Aggregate Functions with Conditional Expressions

SELECT SUM(CASE WHEN product_name = 'Product A' THEN sales_quantity ELSE 0 END) AS Product_A_Sales, SUM(CASE WHEN product_name = 'Product B' THEN sales_quantity ELSE 0 END) AS Product_B_Sales, SUM(CASE WHEN product_name = 'Product C' THEN sales_quantity ELSE 0 END) AS Product_C_SalesFROM SalesData;...

2. Using GROUP_CONCAT Function

SELECT GROUP_CONCAT(CASE WHEN product_name = 'Product A' THEN sales_quantity END) AS Product_A_Sales, GROUP_CONCAT(CASE WHEN product_name = 'Product B' THEN sales_quantity END) AS Product_B_Sales, GROUP_CONCAT(CASE WHEN product_name = 'Product C' THEN sales_quantity END) AS Product_C_SalesFROM SalesData;...

3. Dynamic Pivot with Prepared Statements

SET @sql = NULL;SELECT GROUP_CONCAT( CONCAT( 'MAX(CASE WHEN product_name = ''', product_name, ''' THEN sales_quantity ELSE NULL END) AS ', product_name, '_Sales' )) INTO @sqlFROM ( SELECT DISTINCT product_name FROM SalesData) t;SET @sql = CONCAT('SELECT ', @sql, ' FROM SalesData;');PREPARE stmt FROM @sql;EXECUTE stmt;DEALLOCATE PREPARE stmt;...

Conclusion

Overall, convert rows to columns in MariaDB is important for effective data analysis and reporting. We have seen various methods like aggregate functions with conditional expressions, GROUP_CONCAT function and dynamic pivot with prepared statements the users can efficiently transform data structures to fulfill analytical needs. These techniques offer flexibility and scalability also enabling users to extract valuable insights and make informed decisions based on their data. By mastering these methods, users can take advantage of full potential of their data and drive business success through informed decision–making and strategic planning....