What function should be used to obtain the highest selling price from multiple price columns?

The function that should be used to obtain the highest selling price from multiple price columns is the GREATEST function. GREATEST is designed to take multiple arguments and return the largest value among them. This makes it particularly suited for scenarios where you need to compare values across various columns, such as different selling prices for the same item.

When using GREATEST, you can directly input the price columns that you wish to compare, and it will efficiently evaluate them to return the highest price. This is especially useful in databases and SQL queries, where aggregated or complex comparisons are typically required.

In contrast, other functions like COALESCE are utilized for returning the first non-null value from a list of expressions, which is not aimed at finding a maximum value. IIF is a conditional function that evaluates a situation and returns one of two values based on whether the condition is true or false, instead of comparing multiple values. MAX, while useful for obtaining the maximum value from a single set of data, does not operate across multiple columns simultaneously as GREATEST does. Consequently, GREATEST is the appropriate and efficient choice for determining the highest selling price from several price columns.