Search code examples
sqlsql-order-by

What is the purpose of Order By 1 in SQL select statement?

I'm reading through some old code at work, and have noticed that there are several views with an order by 1 clause. What does this accomplish?

Example:

Create view v_payment_summary AS
SELECT A.PAYMENT_DATE,
       (SELECT SUM(paymentamount)
          FROM payment B
         WHERE PAYMENT_DATE = B.PAYMENT_DATE
           and SOME CONDITION) AS SUM_X,
       (SELECT SUM(paymentamount)
          FROM payment B
         WHERE PAYMENT_DATE = B.PAYMENT_DATE
           and SOME OTHER CONDITION) AS SUM_Y    
FROM payment A    
ORDER BY 1;
Solution

  • This:

    ORDER BY 1

    ...is known as an "Ordinal" - the number stands for the column based on the number of columns defined in the SELECT clause. In the query you provided, it means:

    ORDER BY A.PAYMENT_DATE

    It's not a recommended practice, because:

    1. It's not obvious/explicit
    2. If the column order changes, the query is still valid so you risk ordering by something you didn't intend