問題文
Three ways of writing an equijoin are available and a team has to pick one for a query that will live for years and that joins on one of several columns whose names match. Which choice fits and why?
選択肢
- The form that lists the columns in a using clause fits because it names the pairing and it lets the joined columns be qualified with a table alias.
- The form with the natural keyword fits because it needs no maintenance when a table gains a column and it lets the joined columns be qualified with an alias of their own.
- The form with an explicit condition fits because it names the pairing in the text and it keeps working even when a column with a matching name is added to a table later on.
- The form with the natural keyword fits because it names the pairing in the text and it keeps working when a column with a matching name is added later on.