How to Find the Maximum Value and Its Corresponding Column Name in SQL?

How to Retrieve Both the Maximum Value and Associated Column Name from Multiple Columns

Identifying the maximum value among multiple columns is a common task in data analysis. However, it becomes more complex when you also need to determine the column containing this value.

The GREATEST function in SQL provides a solution to this challenge. It allows you to calculate the maximum value from a set of specified columns:

SELECT GREATEST(col1, col2, col3, ...) AS max_value
FROM table_name
WHERE ...

This query returns the greatest value in the specified columns. However, we still need to determine the column that holds this value.

To accomplish this, we can use a CASE expression within the SELECT statement:

SELECT @var_max_val:= GREATEST(col1, col2, col3, ...) AS max_value,
       CASE @var_max_val WHEN col1 THEN 'col1'
                         WHEN col2 THEN 'col2'
                         ...
       END AS max_value_column_name
FROM table_name
WHERE ...

The CASE expression evaluates the max_value and returns the corresponding column name as max_value_column_name. For example, if max_value is equal to col2, max_value_column_name will be set to 'col2'.

This approach allows you to retrieve both the maximum value and its associated column name, providing valuable insights for data analysis and decision-making.

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