SQL: ORDER BY [列索引]

SELECT ID, FIRST_NAME || ' ' || LAST_NAME
FROM AUTHOR
ORDER BY 2;

SELECT ID, FIRST_NAME || ' ' || LAST_NAME
FROM AUTHOR
ORDER BY FIRST_NAME || ' ' || LAST_NAME;

-- Adding a column has broken the query
SELECT ID, LAST_UPDATE, FIRST_NAME || ' ' || LAST_NAME
FROM AUTHOR
ORDER BY 2;

-- The query is not affected by this change
SELECT ID, LAST_UPDATE, FIRST_NAME || ' ' || LAST_NAME
FROM AUTHOR
ORDER BY FIRST_NAME || ' ' || LAST_NAME;

-- Also, aliasing the expression (to avoid repetition) can work in many dialects
SELECT ID, LAST_UPDATE, FIRST_NAME || ' ' || LAST_NAME AS NAME
FROM AUTHOR
ORDER BY NAME;