from-clause

If only one table-reference is specified, the intermediate result table is simply the result of that table-reference. If more than one table-reference is specified in the FROM clause, the intermediate result table consists of all possible combinations of the rows of the specified table-references (the Cartesian product). Each row of the result is a row from the first table-reference concatenated with a row from the second table-reference, concatenated in turn with a row from the third, and so on. The number of rows in the result is the product of the number of rows in all the individual table-references.

If table-reference has row access controls enforced, table-reference has at least one row permission: the default row permission. When there are multiple row permissions defined for a table-reference, a row access control search condition is derived by applying the logical OR operator to the search condition in each enabled permission. This derived search condition acts as a filter to the table-reference to determine the result table of the table-reference that is accessible to the authorization ID of the subselect.