Order of execution of SQL statements

Before you see a diagram that describes the order in which SQL statements are executed:

(This figure comes from the article SQL statement execution sequence description)

The picture is very good and clearly shows the order of execution of the SQL statement; Today we have a problem that deepens the understanding of the order in which SQL statements are executed.

There is such a table:

The topics are:

Lists the Product ID (item id:product$id) and order quantity for all goods that are contained in more than one order (order number: Xorder$id), ordered in descending order of the commodity ID.

The SQL statements are as follows:

Select Product$id,sum (quantity) from LINEITEM Group by Product$id have count (product$id) > 1 ORDER BY product$id DESC ;

The results are as follows:

Although this example is less of a WHERE clause, it does not affect the way it helps us understand the execution of SQL statements, because WHERE clauses are so common that we understand them already.

Order of execution of SQL statements