Which SQL clause would commonly use the coalesce function to ensure all values are displayed?

The use of the COALESCE function in SQL is primarily seen in the SELECT clause. COALESCE is designed to return the first non-null value in a list of arguments. When writing queries, particularly in the SELECT clause, you might encounter situations where some of the columns can have NULL values. By applying COALESCE, you can ensure that instead of seeing a NULL value in the final output, a default or alternative value is displayed.

For example, if you are selecting multiple columns from a table, some of which might have NULL entries, using COALESCE allows you to define a fallback value. This is particularly useful for reporting or displaying results where having complete information is essential. If the DATA column may contain NULLs, using COALESCE(DATA, 'N/A') in the SELECT clause helps to present a user-friendly output rather than an empty or NULL entry.

The other clauses do serve important roles in SQL constructs but are not typically associated with the COALESCE function in the same manner. The WHERE clause filters records based on specified conditions, the FROM clause specifies the tables from which to retrieve data, and the ORDER BY clause determines the order in which the results are presented. None of these utilize COALESCE to manage