What is the correct order of clauses in a SELECT statement when all are present?

The correct order of clauses in a SELECT statement is important for the proper execution and retrieval of data in SQL. The standard sequence begins with the SELECT clause, which specifies the columns that you want to retrieve, followed by the FROM clause, which identifies the source tables. Next is the WHERE clause, where you can filter records based on specific conditions. After filtering, the GROUP BY clause is used to aggregate rows that have the same values in specified columns. If you need to filter these groups, you use the HAVING clause next, which allows conditions to be applied to grouped data. Finally, the ORDER BY clause allows you to sort the results of the query based on one or multiple columns.

This order ensures that the SQL statement is logically structured, allowing for effective processing of data as intended. Following this sequence makes it clearer for the SQL engine to understand the operations in the correct order, leading to accurate results. Understanding this hierarchy is essential for constructing effective SQL queries and is a core part of advanced programming techniques in SAS.