MySQL 8.0 Release Notes
MySQL 8.0 Source Code Documentation
The maximum number of tables that can be referenced in a single
join is 61. This includes a join handled by merging derived
tables and views in the FROM clause into the
outer query block (see
Section 8.2.2.4, “Optimizing Derived Tables, View References, and Common Table Expressions
with Merging or Materialization”). It also applies
to the number of tables that can be referenced in the definition
of a view.