Order by multi-field sorting query in SQL

In SQL, order by has N Different usage methods. Yesterday I talked about an order by with an equal sign. Here we will introduce how order by sorts multiple fields at the same time.

Two fields can be added after order by, which are separated BY commas.

Example

The Code is as follows:	Copy code
Select a1, a2, a3 from t1 order by a1 desc, a2 asc

Next let's take a look at other instances.

F1 is in ascending order, f2 is in descending order, and SQL is written in this way

Order by f1, f2 DESC

You can also write it like this to make it clearer:

Order by f1 ASC, f2 DESC

If both are in descending order, you must use two desc

Order by f1 DESC, f2 DESC