How Can I Find the Maximum Value and Its Corresponding Column Name in a SQL Table?

Determining the Maximum Value and Corresponding Column Name in Multiple Columns

In the realm of database queries, one common task is to identify the maximum value among multiple columns. While the MAX function provides an elegant solution for finding the greatest value, it does not reveal the column associated with that value. To address this issue, we delve into a unique approach involving the GREATEST function.

Leveraging the GREATEST function, you can ascertain the maximum value from a set of columns while simultaneously retrieving the corresponding column name. The following SQL statement showcases this technique:

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

In this statement, we store the maximum value in the variable @var_max_val. Subsequently, we employ a CASE statement to evaluate the @var_max_val variable against each column individually. The column name with the matching maximum value is then assigned to the max_value_column_name variable.

This technique not only determines the maximum value but also effortlessly retrieves the associated column name, providing a comprehensive understanding of the data distribution. It proves particularly useful when you need to analyze multiple columns and identify the column with the highest value, making it a valuable addition to your SQL toolkit.

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